The 10 Senate seats most likely to flip in 2018

Republicans are increasingly focused on the Senate as GOP donors and strategists grow more pessimistic about their ability to hold onto the House.

The prospect of a Democratic House has made Republicans desperate to take advantage of a favorable Senate map to hold or expand their majority in the upper chamber.

Republicans still have a strong chance of gaining seats, with 10 Democrats up in states President TrumpDonald John TrumpWhat the Mueller report tells us about Putin, Russia and Trump's election Fox's Brit Hume fires back at Trump's criticism of the channel Anti-US trade war song going viral in China MORE won in 2016. But while the GOP is mostly on the offensive, the party also faces the prospect of losing some seats.

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Here’s a look at the top 10 seats most likely to flip in 2018:


1. Sen. Dean HellerDean Arthur HellerThis week: Barr back in hot seat over Mueller report Trump suggests Heller lost reelection bid because he was 'hostile' during 2016 presidential campaign Trump picks ex-oil lobbyist David Bernhardt for Interior secretary MORE (R-Nev.)

Heller is the only Republican incumbent defending a seat in a state Democratic presidential nominee Hillary ClintonHillary Diane Rodham ClintonWhat the Mueller report tells us about Putin, Russia and Trump's election Steve Bullock puts Citizens United decision at center of presidential push Feehery: A whole new season of 'Game of Thrones' MORE won in 2016 — bad news for him as Democratic enthusiasm surges. His opponent, Rep. Jacky RosenJacklyn (Jacky) Sheryl RosenLawmakers introduce legislation to improve cyber workforce funding Dem lawmakers accuse DHS, HHS of giving them misleading information on family separations This week: Barr back in hot seat over Mueller report MORE (D), has posted strong fundraising numbers and is trying to press Heller for his waffling on the GOP health-care repeal and his public role in crafting the GOP tax bill.

But Heller has recently seen a spate of good news that’s improved his chances of surviving in November. Primary challenger Danny Tarkanian dropped out of the race, allowing the senator to avoid making overtures to the GOP’s right flank that could hurt him in the general election. Republicans are also slowly cutting into Democrats’ voter registration advantage in Nevada.

2. Sen. Claire McCaskillClaire Conner McCaskillBig Dem names show little interest in Senate Gillibrand, Grassley reintroduce campus sexual assault bill Endorsements? Biden can't count on a flood from the Senate MORE (D-Mo.)

McCaskill has always faced a tough road to reelection. She’s one of just three Democrats elected statewide in Missouri, which Trump won by almost 20 points. And the GOP is already seizing on McCaskill’s ardent support for Clinton in 2016 as a way to rile up the base.

Still, she’s won a reputation as a strong campaigner and a consistently prolific fundraiser this cycle.

State Attorney General Josh Hawley is still considered a top GOP recruit. But Republicans are closely watching his first-quarter fundraising haul following grumblings about his disappointing fundraising pace last year. The investigations into blackmail allegations against Missouri Gov. Eric Greitens (R) could add a tinge of scandal to the Republican brand in the state.

3. Sen. Joe DonnellyJoseph (Joe) Simon DonnellyObama honors 'American statesman' Richard Lugar Former GOP senator Richard Lugar dies at 87 Ralph Reed: Biden is a 'formidable and strong candidate' MORE (D-Ind.)

The GOP primary between Rep. Luke MesserAllen (Luke) Lucas MesserYoder, Messer land on K Street House GOP to force members to give up leadership positions if running for higher office Indiana New Members 2019 MORE, Rep. Todd RokitaTheodore (Todd) Edward RokitaFemale Dems see double standard in Klobuchar accusations House passes year-end tax package Indiana New Members 2019 MORE and businessman Mike Braun remains one of the nastiest in the nation. The bruising primary fight will also draw down GOP cash reserves before the general election.

The ferocity of the primary gives Donnelly space to position himself as a bipartisan legislator, and he posted his best fundraising total of his career last quarter. But Donnelly will still have a rough go in Vice President Pence’s backyard. The Democrat’s fundraising still falls far short of the totals raised by many other Democratic incumbents, and his Republican challenger will have months to build his funds back up.

4. Arizona’s open seat (vacated by GOP Sen. Jeff FlakeJeffrey (Jeff) Lane FlakeJeff Daniels blasts 'cowardice' of Senate Republicans against Trump WANTED: A Republican with courage Protesters who went viral confronting Flake cheered at award event MORE)

Both parties think their leading candidates can win in Arizona. Reps. Martha McSallyMartha Elizabeth McSallyBolton emerges as flashpoint in GOP debate on Iran Senate Republicans running away from Alabama abortion law McSally to introduce military sexual assault reform bill MORE (R) and Kyrsten Sinema (D) are strong fundraisers who know how to win tough fights. McSally is a veteran who can straddle the line between appealing to the right and to moderate voters, while Sinema is a Blue Dog Democrat with a compelling story who Democrats believe can compete statewide.

Sinema is a virtual lock for the Democratic nomination, but McSally has a rockier path in the GOP primary. She faces former state Sen. Kelli Ward and former Maricopa County Sheriff Joe Arpaio — two controversial candidates who could steer the race to the right. Arizona’s August primary is held late in the cycle, giving the GOP nominee just 10 weeks to recover from a potentially rough primary.

5. Sen. Heidi HeitkampMary (Heidi) Kathryn HeitkampOn The Money: Stocks sink on Trump tariff threat | GOP caught off guard by new trade turmoil | Federal deficit grew 38 percent this fiscal year | Banks avoid taking position in Trump, Dem subpoena fight Fight over Trump's new NAFTA hits key stretch Former senators launching effort to help Dems win rural votes MORE (D-N.D.)

Republicans caught a break when they convinced Rep. Kevin CramerKevin John CramerBolton emerges as flashpoint in GOP debate on Iran Trump's immigration push faces Capitol Hill buzzsaw Lawmakers introduce legislation to improve cyber workforce funding MORE to mount a late bid against Heitkamp. Cramer has made his campaign about fierce loyalty to Trump, who won the state by 36 points in 2016. Cramer can also run on the statewide name recognition he’s built up as a three-term congressman in an at-large seat.

But Republicans had wavered on Cramer before, looking for other alternatives to the gaffe-prone congressman before ultimately settling on him as the top choice. And while Trump repeatedly pushed Cramer to run, the president has also been on good terms with Heitkamp, who has appeared on stage with him in North Dakota and flew on Air Force One.

The escalating trade war between Trump and China could also dampen the GOP’s prospects. China’s retaliatory tariffs threaten to hurt jobs in the agriculture-heavy state, an issue that could weigh on Cramer.

6. Sen. Bill NelsonClarence (Bill) William NelsonRepublicans amp up attacks on Tlaib's Holocaust comments The muscle for digital payment Rubio says hackers penetrated Florida elections systems MORE (D-Fla.)

Gov. Rick Scott’s (R) Monday entry into the race is a big win for Republicans, who previously faced long odds taking the swing-state seat. Scott will give Nelson the toughest race of his Senate career. The two-term governor has a formidable campaign operation, and his vast personal wealth will be an asset in Florida’s pricey media markets.

But this will also be a much different race for Scott. In the past, he’s only run in Republican wave years, winning by razor-thin margins even when the political atmosphere favored the GOP. And his closeness to Trump, who personally recruited him for the Senate race, could also be a potential drag in a state the president won by a little more than a point.

7. Sen. Joe ManchinJoseph (Joe) ManchinLabor head warns of 'frightening uptick' in black lung disease among miners Labor leader: Trump has stopped erosion of coal jobs Overnight Energy: States fight Trump rollback of Obama lightbulb rules | Greens seek hearing over proposed rule on energy efficiency tests | Top Dem asks GAO to investigate climate threat MORE (D-W.Va.)

Manchin faces an uphill climb keeping his seat in a state that went for Trump by nearly 42 points. But Manchin could benefit from a brutal GOP primary fight.

The two-person race between Rep. Evan JenkinsEvan Hollin JenkinsWest Virginia New Members 2019 Republican Carol Miller holds off Democrat in West Virginia House race Trump to fundraise for 3 Republicans running for open seats: report MORE and state Attorney General Patrick Morrisey has been upended by a surge from former coal CEO Don Blankenship. Blankenship is polling well in the primary, even after serving a prison term over a fatal mine explosion. While Blankenship has the wealth to dominate the airwaves in the primary fight, Republicans fear he can’t win over more moderate voters in November.

Trump is going on the offensive against Manchin, after an initial show of bipartisanship with the senator. Flanked by Jenkins and Morrisey at a recent roundtable in West Virginia, Trump slammed Manchin for his vote against the tax overhaul.

8. Sen. Tammy BaldwinTammy Suzanne BaldwinThis week: House to vote on bill to ban LGBTQ discrimination Overnight Defense — Presented by Huntington Ingalls Industries — Pentagon approves transfer of .5B to border wall | Dems blast move | House Dem pushes Pelosi to sue over Trump's Yemen veto Pentagon approves transfer of .5B to Trump border wall from Afghan forces, other accounts MORE (D-Wis.)

Wisconsin was once seen as a reach for Republicans. But the barrage of attack ads from outside GOP groups have softened Baldwin up ahead of November, prompting a flurry of Democratic spending meant to shore up the senator.

It’s still unclear who will emerge from the contentious GOP primary. Marine Corps veteran Kevin Nicholson, a former Democrat, is the pick of top conservative groups, but state Sen. Leah Vukmir has some big Wisconsin names in her corner.

9. Sen. Jon TesterJonathan (Jon) TesterGOP angst grows amid Trump trade war Overnight Defense — Presented by Huntington Ingalls Industries — Pentagon approves transfer of .5B to border wall | Dems blast move | House Dem pushes Pelosi to sue over Trump's Yemen veto Pentagon approves transfer of .5B to Trump border wall from Afghan forces, other accounts MORE (D-Mont.)

Tester has built his campaign message around his willingness to work with Trump, a key argument in a state the president won by 20 points. And while the GOP hopefuls — state auditor Matt Rosendale, Judge Russ Fagg and businessman Troy Downing — are more focused on attacking Tester than blasting each other, the fluid primary still gives Tester some room.

Fortunately for Tester, Democrats aren’t extinct in Montana — Gov. Steve Bullock (D) cruised to reelection in 2016, even as Trump dominated.

Still, Tester has never won reelection with the majority of the vote, winning instead after a Libertarian candidate siphoned off votes from the GOP. This year, the presence of both a Green Party candidate and a Libertarian candidate on the ballot complicates that calculus.

10. Sen. Sherrod BrownSherrod Campbell BrownOn The Money: Judge upholds House subpoena for Trump financial records | Trump vows to appeal ruling by 'Obama-appointed judge' | Canada, Mexico lift retaliatory tariffs on US | IRS audit rate falls Lawmakers grapple with the future of America's workforce The Hill's Morning Report - Presented by Pass USMCA Coalition - Restrictive state abortion laws ignite fiery 2020 debate MORE (D-Ohio)

Judging only by its 2016 numbers, Ohio should be more competitive. The state is drifting right — Trump won by 8 points, and all of the top statewide officeholders are Republicans. Still, the GOP has struggled to dent Brown, and he’s pulled in impressive fundraising totals.

Republican front-runner Rep. Jim RenacciJames (Jim) B. RenacciGOP rep: If Mueller had found collusion, 'investigation would have wrapped up very quickly' House Ethics Committee extends probe into Renacci Sherrod Brown says he has 'no real timetable' for deciding on 2020 presidential run MORE has faced a spate of bad headlines in recent weeks about accusations that he failed to disclose political donations while registered as a lobbyist. He is looking to best businessman Mike Gibbons in the primary.

Other races to watch: Sen. Bob CaseyRobert (Bob) Patrick CaseyWhy Congress needs to bring back tax deduction for worker expenses Biden cements spot as 2020 front-runner The Hill's Morning Report - Biden's bid gets under Trump's skin MORE Jr. (D) still appears in the driver’s seat in Pennsylvania, even as GOP Rep. Lou BarlettaLouis (Lou) James BarlettaTrump's most memorable insults and nicknames of 2018 GOP trading fancy offices, nice views for life in minority Casey secures third Senate term over Trump-backed Barletta MORE steps up his fundraising. Former Tennessee Gov. Phil Bredesen (D) raised eyebrows by polling ahead of GOP Rep. Marsha BlackburnMarsha BlackburnGraham warns of 5G security threat from China Export-Import Bank back to full strength after Senate confirmations Trump, Senate GOP discuss effort to overhaul legal immigration MORE for the seat currently held by retiring Sen. Bob CorkerRobert (Bob) Phillips CorkerJeff Daniels blasts 'cowardice' of Senate Republicans against Trump Corker: 'I just don't' see path to challenge Trump in 2020 Ex-GOP Sen. Corker: Trump primary would be 'good thing for our country' MORE (R), but she has time to boost her statewide name recognition. Mississippi’s special election is home to a four-way jungle primary that’s tough to handicap. And while Rep. Beto O’Rourke (R-Texas) is setting fundraising records, it’s unclear whether it’s enough to defeat Sen. Ted CruzRafael (Ted) Edward CruzCruz slams Jim Carrey's 'vicious, angry' painting of Alabama governor after abortion ban Eye-popping number of Dems: I can beat Trump 'SleepyCreepy Joe' and 'Crazy Bernie': Trump seeks to define 2020 Dems with insults MORE (R-Texas).