The 2018 midterm season is upon us and the storyline in the House and Senate will be the balance of power and whether Republians can hold their majorities in both chambers. The momentum is tipping toward Democrats big time, particularly in House races, according to the latest CNN reporting. But Democrats are defending more than two dozen Senate seats, including 10 in states President Donald Trump won in 2016. Republicans have just eight Senate seats up for re-election.
Here's a look at where things stand and what's coming up in each of the 2018 midterm primaries. A number of special elections are included.
Tuesday, March 6
Races to watch: TX-07 (Hurd), TX-23 (Culberson), TX-32 (Sessions)
November outlook: Three-term GOP Rep. Will Hurd is running for re-election in this Clinton-won 2016 district in San Antonio. The anticlimactic outcome of the immigration debate could have an impact on his prospects in the fall, as CNN rates this race as a toss-up. GOP Reps. John Culberson and Pete Sessions could find themselves in tough races. Culberson goes into 2018 with a slight cash disadvantage and faces demographic changes trending Democratic in this Houston-based district, and liberal pockets of northern Dallas could threaten Sessions. Both races are ranked lean Republican. Sen. Ted Cruz will almost certainly face Democratic Rep. Beto O'Rourke in his own bid for re-election. CNN currently rates the race likely Republican, but O'Rourke out-raised Cruz in the final two quarters of 2017, and this contest is worth watching as the midterm cycle progresses.
Election Day: Tuesday, March 13
PA-18 special election
The special election to fill former GOP Rep. Tim Murphy's seat will be closely watched, as both sides are pouring money and high profile surrogates -- including Trump and former Vice President Joe Biden -- into the district in Pittsburgh's suburbs. A recent Monmouth poll showed Democratic challenger Conor Lamb within 3 points of Republican Rick Saccone. Murphy resigned in October after revelations involving an abortion from the woman with whom he was having an affair became public.
Primary date: Tuesday, March 20
Races to watch: IL-06 (Roskam), IL-12 (Bost), IL-13 (Davis), IL-14 (Hultgren)
November outlook: Four Republican-held House seats are seen as competitive in the land of Lincoln. Rep. Peter Roskam, who came into Congress during the Democratic wave of 2006, may face a tight race in his Clinton-won district of Chicago's west suburbs. A loss for Rep. Mike Bost in southwest Illinois could portend major Democratic wins in the fall. Bruce Rauner is one of the most endangered Republican governors up this year as well.
Election Day: Tuesday, April 24
- AZ-08 special election
GOP Rep. Trent Franks resigned after the House Ethics Committee opened an investigation into allegations of sexual harassment from two female former staffers. Republican state Sen. Debbie Lesko emerged from a 12-person primary in February and will face off against Democrat Hiral Tipirneni, an emergency room doctor. This is seen as a safe Republican seat, but Democrats are making a late push to attempt to make it competitive.
Primary date: Tuesday, May 8
- OH-12 special primary
GOP Rep. Pat Tiberi resigned in January to take over as head of the Ohio Business Roundtable. Democrats look likely to nominate former Franklin County Sheriff Zach Scott or Franklin County Recorder Danny O'Connor. The Republicans have a wide-open field, with state Sen. Kevin Bacon among the leading contenders. CNN rates the race as likely Republican.
Races to watch: Indiana US Senate race
November outlook: Sen. Joe Donnelly is one of the most vulnerable Democrats up for re-election this year. Trump beat Hillary Clinton in the Hoosier state by 19 points in 2016. Two GOP representatives -- Todd Rokita and Luke Messer -- will battle it out on May 8 to determine who takes on Donnelly in November.
- North Carolina
Races to watch: NC-02 (Holding), NC-09 (Pittenger), NC-13 (Budd)
November outlook: Three Republican-held seats will be important to watch in North Carolina. Reps. George Holding, Robert Pittenger and Ted Budd all won re-election in 2016 with at least 55% of the vote, but they could be at risk if Democrats win big in the fall.
Races to watch: OH-01 (Chabot), OH-12 (open, Tiberi -- see above)
November outlook: The race to succeed Gov. John Kasich will be an important race to watch, as former Obama Consumer Financial Protection Bureau head Richard Cordray seeks to bring his party back into the governor's mansion, possibly with the help of populist Sen. Sherrod Brown who is up for re-election in the Buckeye State. Popular Republican Rep. Steve Chabot's Cincinnati seat will be critical for the GOP to keep the House. This race is rated as likely Republican.
- West Virginia
Races to watch: West Virginia US Senate
November outlook: Democrat Joe Manchin will face a tough re-election fight for this Senate seat. Trump beat Clinton by over 40 points here. Manchin -- a former two-term governor -- hopes his moderate views and history with the state will put him over the top, as his state trends further right. The GOP primary is competitive, with Rep. Evan Jenkins battling Attorney General Patrick Morrisey and ex-convict Don Blankenship, former CEO of Massey Energy Co.
Primary date: Tuesday, May 15
Races to watch: NE-02 (Bacon)
November outlook: Rep. Don Bacon was the only Republican to beat a Democratic incumbent in 2016. Democrats have this Omaha-based seat in their sights in their quest to take back the majority in the House. This seat is rated as a toss-up by CNN. GOP Sen. Deb Fischer is up for re-election.
Races to watch: PA-01 (Fitzpatrick), PA-05 (open, Meehan), PA-06 (Costello), PA-07 (open, Dent), PA-08 (Cartwright), PA-10 (Perry), PA-17 (Rothfus)
November outlook: Democratic Sen. Bob Casey could face a tough re-election if Republicans raise enough money and run a strong campaign in the commonwealth. CNN currently rates seven of the 18 House seats as key races to watch. New districts that were handed down by the state Supreme Court after ruling the current lines were gerrymandered in favor of the GOP could put more seats in play come the fall.
Primary date: Tuesday, May 22
Races to watch: AR-02 (Hill)
November outlook: Republicans are strongly favored to hold all four congressional seats in Arkansas, but Little Rock-based Rep. French Hill faces a solid Democratic challenger in state Rep. Clarke Tucker. CNN rates it as likely Republican. Gov. Asa Hutchinson is up for re-election as well and is widely seen as a safe bet for Republicans too.
Races to watch: GA-06 (Handel), GA-07 (Woodall)
November outlook: If Democrats want to pick up seats in Georgia, they may look at the 6th and 7th districts. GOP Rep. Karen Handel won a tough battle to succeed former Health and Human Services Secretary Tom Price in 2017, despite a major cash influx for Democrat Jon Ossoff, which will make it difficult for them to win. But if 2018 turns into a wave for Democrats, Handel and Rep. Rob Woodall could become vulnerable. CNN currently rates both races as likely Republican. The open governor seat may influence the race, should it become competitive, depending on the outcome of the primaries, in which both parties may move farther from the center than their respective party leaders in the Peach State.
Races to watch: KY-06 (Barr)
November outlook: Three-term Republican Rep. Andy Barr's race is currently rated as lean Republican by CNN. He has won at least 60% of the vote in each election, but Democrats will likely field strong competition, which could put this seat in play.
Primary date: Tuesday, June 5
Despite a surprise victory from Democrat Doug Jones in the special election for the Senate last year, no Alabama seat is seen as competitive this year for either party, including Republican Gov. Kay Ivey as she seeks her first full term.
Races to watch: CA-07 (Bera), CA-10 (Denham), CA-21 (Valadao), CA-25 (Knight), CA-39 (open, Royce), CA-45 (Walters), CA-48 (Rohrabacher), CA-49 (open, Issa), CA-50 (Hunter)
November outlook: Eight of the nine House seats rated as competitive by CNN are currently held by Republicans, some of which are in districts Clinton won in 2016. If Democrats are going to take back the House, they will need (and may get) a few of these to do it. While the Senate seat is expected to stay in Democratic hands, the primary and general election against Sen. Dianne Feinstein could turn competitive, as she will likely face a more progressive Democrat in the fall due to the state's jungle primary laws. California has a competitive governor's race to replace outgoing Gov. Jerry Brown, with top contenders in Lt. Gov. Gavin Newsom and former Los Angeles Mayor Antonio Villaraigosa, both Democrats.
Races to watch: IA-01 (Blum), IA-03 (Young)
November outlook: Two-term GOP Rep. Rod Blum's race is rated as a toss-up. Blum won 51% and 54% in his northeastern Iowa district during his first two campaigns but could face his toughest race in a year that could favor Democrats. Fellow sophomore Rep. David Young is also being heavily targeted by the Democratic Congressional Campaign Committee. Both of these districts voted for President Barack Obama in 2008 and 2012 before flipping to Trump in 2016.
November outlook: Sen. Thad Cochran's upcoming retirement -- announced in early March -- sets up a special US Senate election in Mississippi, meaning both of the state's Senate seats will be on the ballot come November. GOP Sen. Roger Wicker is up for re-election and is facing a primary challenge from state Sen. Chris McDaniel -- who nearly knocked off Cochran in a high-profile primary race in 2014. Mississippi's House races are not seen as competitive this year.
Races to watch: MT Sen; MT-AL
November outlook: Democratic Sen. Jon Tester will face voters for the third time, but this year he's coming on the heels of Trump's 21-point win in Big Sky Country. Republicans see this seat as a perfect opportunity for a flip, but party members have yet to coalesce around one candidate. Tester's significant money advantage gives him a slight edge, as CNN rates this race lean Democrat. Controversial GOP Rep. Greg Gianforte's race is rated as likely Republican at the beginning of 2018.
- New Jersey
Races to watch: NJ-02 (open, LoBiondo), NJ-03 (MacArthur), NJ-05 (Gottheimer), NJ-07 (Lance), NJ-11 (open, Frelinghuysen)
November outlook: Five of New Jersey's 12 congressional seats are on CNN's competitive ratings this year. The two open seats left by retiring GOP Reps. Rodney Frelinghuysen and Frank LoBiondo are seen as big targets for Democrats to flip. Trump's unpopularity in the Garden State could curtail the GOP's attempts to rebuild after losing the governor's mansion last year. Democratic Sen. Bob Menendez is up for a third term this year, in a race that CNN ranks as solid Democrat.
- New Mexico
Races to watch: NM-02 (open, Pearce)
November outlook: Four-term GOP Rep. Steve Pearce is running for governor, which leaves a slight opening for Democrats in this southern New Mexico district. The area trends conservative, as CNN rates this House race as likely Republican. Pearce will have a tough race to succeed Republican Gov. Susana Martinez, whose approval ratings have fallen as she ends her second term. Democratic Sen. Martin Heinrich is up for re-election.
- South Dakota
Primary date: Tuesday, June 12
Races to watch: ME-02 (Poliquin)
November outlook: Democrats would like to take back the last Republican-held seat in Maine's 2nd District, but that could prove tougher than expected. The district's support of Trump (giving him an electoral vote in 2016) and Rep. Bruce Poliquin's strong cash advantage will be tough to beat in this northern Maine seat. CNN currently rates the race as likely Republican, though the governor's race could provide Democrats a place to flip a state executive seat from red to blue. Independent Sen. Angus King is up for re-election.
- North Dakota
Races to watch: North Dakota US Senate
November outlook: Democrat Heidi Heitkamp faces a tough re-election for her Senate seat, and she's raising the money for a fight. GOP Rep. Kevin Cramer said in January that he would not run for the seat before reversing course and announcing his candidacy in mid-February. Trump won the state by 36 points, and Republicans are determined to beat Heitkamp. CNN initially rated this race as lean Democrat, but with Cramer's candidacy, it is now a toss-up.
Races to watch: NV Sen; NV-03 (open, Rosen), NV-04 (open, Kihuen)
November outlook: Looking to capitalize on Clinton's 2016 win and the state's trend toward Democrats, Nevada will be home to some of the country's toughest competitions this year for the House, the Senate and the Governor's Mansion. Democratic Rep. Jacky Rosen is challenging Republican Sen. Dean Heller, in a race rated as toss-up by CNN. Rosen leaves her current House seat open, which CNN also rates as a toss-up. After being accused of sexual harassment, Democratic Rep. Ruben Kihuen announced he won't seek reelection. His central Nevada district, including the Las Vegas suburbs, gives Democrats a slight advantage, as CNN rates this race lean Democrat.
- South Carolina
Races to watch: VA-02 (Taylor), VA-05 (Garrett), VA-7 (Brat), VA-10 (Comstock)
GOP Rep. Barbara Comstock's DC exurb district is a big target for a Democratic flip in November. This will most likely be the most competitive race in the state this year, followed by that of Rep. Scott Taylor, a Republican who represents the hometown of the state's Democratic governor. Taylor's strong military background and willingness to work across the aisle give him an advantage, as CNN ranks this race as lean Republican. Sen. Tim Kaine, the 2016 Democratic vice presidential candidate, has yet to see a strong candidate against him in the fall. CNN rates his race as likely Democrat.
Primary date: Tuesday, June 19
- District of Columbia
Primary date: Tuesday, June 26
Races to watch: CO-06 (Coffman)
November outlook: GOP Rep. Mike Coffman will face an intense battle for a sixth term, as this district, which includes Denver suburbs, voted for Clinton in 2016. This diverse district with a growing Hispanic population has trended Democratic, which in part is why CNN ranks the race as a toss-up. The governor's race could affect down-ticket races, though the state as a whole has trended Democratic as well over the past few elections.
November outlook: No congressional race is viewed as competitive in Maryland, but a pending Supreme Court case on gerrymandering districts in favor of Democrats could change the map here. Republican Gov. Larry Hogan is popular in the state, which could help him separate himself from the national party -- not viewed as favorably here -- to win a second term. Chelsea Manning, the former Army intelligence analyst convicted of disclosing classified information to WikiLeaks, is running for Senate as a Democrat.
- New York
Races to watch: NY-01 (Zeldin), NY-11 (Donovan), NY-19 (Faso), NY-22 (Tenney), NY-24 (Katko)
November outlook: Five GOP congressional races are ranked somewhat competitive by CNN. Reps. John Faso and Claudia Tenney have lagged behind in fundraising going into 2018, as CNN rates their seats as toss-ups. Democrats are hoping their national popularity will help them unseat Faso in his Hudson Valley district. Though Tenney represents the more conservative Binghamton area, Obama did well there, showing the power of a motivated Democratic Party they hope to capitalize on again. With a governor and Senate race (Kirsten Gillibrand's seat is ranked solid Democrat heading into her re-election bid), the Big Apple could be the home of big wins for Democrats.
Races to watch: UT-04 (Love)
November outlook: Utah may not house the most competitive races of 2018, but the Beehive State will be buzzing. Former 2012 Presidential nominee Mitt Romney recently announced his run for the open Senate seat there, which is ranked as solid Republican by CNN. GOP Rep. Mia Love will face a tough race this fall and is currently lagging behind in fundraising. Her Salt Lake City district is a strong Republican area, as CNN ranks this race as lean Republican.
Primary date: Thursday, August 2
Races to watch: TN Sen
November outlook: Tennessee's nine districts are not ranked as competitive, though the Senate seat left open by Republican Bob Corker's retirement, reconsideration and final decision to retire has sparked an interest on both sides of the aisle. It will be a tough race for Democrats, though popular former Gov. Phil Bredesen could give the GOP a run for its money, even though Trump won the state by 26 points. CNN ranks this race as likely Republican.
Primary date and Election Day: Tuesday, August 7
- OH-12 special election
Special election for former GOP Rep. Pat Tiberi's seat. Tiberi resigned to join the Ohio Business Roundtable. CNN rates this Columbus-suburb district as likely Republican.
Races to watch: KS-02 (open, Jenkins), KS-03 (Yoder)
November outlook: The Kansas side of Kansas City is a potential risk for Republicans. As GOP Rep. Kevin Yoder seeks a fifth term, he's weighed down by a district that narrowly voted for Clinton in 2016. Yoder's cash advantage gives him a good start, as CNN rates this race as lean Republican.
Races to watch: MI-06 (Upton), MI-07 (Walberg), MI-08 (Bishop), MI-11 (open, Trott)
November outlook: Four Michigan Republican-held seats are viewed as competitive by CNN, leading with retiring Rep. David Trott's Detroit-suburb district ranked as toss-up. Rep. Michael Bishop will seek a third term in his Lansing-based district, where Trump expanded the margin of the two past presidential winners, though he's been outraised by his Democratic opponent. CNN rates this race as lean Republican. A good night for Democrats in November could put GOP Reps. Fred Upton and Tim Walberg at risk, but for now, their races are ranked as likely Republican.
Races to watch: Missouri US Senate
November outlook: Democratic Sen. Claire McCaskill will most likely face the toughest race she's experienced as she seeks a third term. Coming off the heels of Trump's 19-point win, Republicans are intent on flipping this seat in the Show Me state to their side. Democratic strength nationwide helped McCaskill in 2006 and 2012, which makes her party's momentum heading into November a critical factor in this race.
- Washington state
Races to watch: WA-05 (McMorris Rodgers), WA-08 (open, Reichert)
November outlook: GOP Rep. Dave Reichert's retirement gives Democrats a big opening in this district of Seattle suburbs where Clinton won in 2016. CNN rates this race as a toss-up. House Republican Caucus leader Cathy McMorris Rodgers has a significant money lead and history in the district, giving her a significant advantage over her Democratic rivals, but momentum on the left cannot be ignored in this east Washington district. CNN ranks this race as likely Republican. Democratic Sen. Maria Cantwell is up for re-election.
Primary date: Saturday, August 11
Democratic Sen. Mazie Hirono is up for re-election.
Primary date: Tuesday, August 14
Democratic Sen. Chris Murphy is up for re-election.
Races to watch: MN-01 (open, Walz), MN-02 (Lewis), MN-03 (Paulsen), MN-07 (Peterson), MN-08 (open, Nolan)
November outlook: Three congressional districts in Minnesota are ranked as toss-ups by CNN. Two Democratic-held seats by retiring Reps. Tim Walz and Rick Nolan are targets for Republicans, hoping to use Trump's wins as a springboard to victory. Democrats are targeting freshman Rep. Jason Lewis, whose district covers the southern suburbs of Minneapolis. Lewis's likely Democratic opponent outraised him more than 2-to-1 in the final fundraising quarter of 2017, but the incumbent still holds an overall cash on hand advantage. Democratic Sen. Tina Smith is running to serve the rest of former Sen. Al Franken's term. Democratic Sen. Amy Klobuchar is up for re-election.
Independent Sen. Bernie Sanders is up for re-election.
Races to watch: WI Sen; WI-03 (Kind), WI-06 (Grothman)
November outlook: Democratic Sen. Tammy Baldwin will face a tough re-election in the Badger State, coming off Trump's historic 2016 win there. A Republican presidential candidate hadn't won the state in the 28 years prior. CNN currently rates this race as lean Democrat.
Primary date: Tuesday, August 21
Republican Sen. John Barrasso is up for re-election.
Primary date: Tuesday, August 28
Races to watch: AZ Sen; AZ-01 (O'Halleran), AZ-02 (open, McSally), AZ-09 (open, Sinema)
November outlook: If Democrats have any chance of taking back the Senate, they will have to win in Arizona. Republican Jeff Flake's retirement opened the seat up, and both sides are already campaigning hard for it. Trump's immigration policies and positions will most likely embolden supporters and detractors to come to the polls in the Grand Canyon State, which he won by only 4 points in 2016. The race is ranked as a toss-up by CNN. Republicans former Sheriff Joe Arpaio and former state Sen. Kelli Ward are both running to fill Flake's seat.
Races to watch: FL Sen; FL-07 (Murphy), FL-13 (Crist), FL-18 (Mast), FL-26 (Curbelo), FL-27 (open, Ros-Lehtinen)
November outlook: Democrats could show some strength in Florida, where one Republican-held seat is already ranked as lean Democrat by CNN. GOP Rep. Carlos Curbelo is in danger of losing his seat composing the southern tip of the state. GOP Rep. Tom Rooney is retiring rather than seeking a sixth term this fall. Rooney represents an overwhelmingly Republican district south of Orlando and Tampa that Trump won by 27 percentage points in 2016 -- so it's likely to remain in GOP hands in November. Democrat Bill Nelson could face a tough re-election for the Senate with a strong candidate like current Gov. Rick Scott, who has not declared. This race is currently ranked lean Democrat.
Primary date: Tuesday, September 4
Democratic Sen. Elizabeth Warren is up for re-election.
Primary date: Thursday, September 6
Democratic Sen. Tom Carper is up for re-election.
Primary date: Tuesday, September 11
- New Hampshire
Races to watch: NH-01 (open, Shea-Porter), NH-02 (Kuster)
November outlook: Both of New Hampshire's congressional seats are viewed as competitive this year. With the retirement of Democratic Rep. Carol Shea-Porter, her district has flipped between both parties multiple times over the past decade. This seat is currently ranked as a toss-up by CNN. Democrat Ann Kuster's race will most likely not be as as competitive, but both parties have the history and know-how to win in the Granite State. CNN currently ranks this race as likely Democrat.
Primary date: Tuesday, September 12
- Rhode Island
Democratic Sen. Sheldon Whitehouse is up for re-election.
Election Day: Tuesday, November 6
- Louisiana (open primaries)
Runoff date: Tuesday, December 4
- Georgia state/local runoffs
Runoff date: Saturday, December 8
- Louisiana runoffs
Tuesday, January 8
- Georgia federal runoffs
This post will be updated repeatedly.
Corrections: Rep. Todd Rokita's last name was initially misspelled. A reference to Rep. Jason Lewis' fundraising has been clarified. The last name of Zach Scott has been corrected and his job title now reflects that he is no longer sheriff of Franklin County, Ohio.