10 Senate seats that could flip in 2018

Democrats reeling from a devastating election face a daunting task: the 2018 Senate map.

It favors Republicans in a big way. The GOP will be defending just eight seats, while Democrats must fight for 23 — plus another two held by independents who caucus with Democrats.

What’s worse is the fact that many of the seats they must defend are in states won by Republican Donald TrumpDonald John TrumpFive challenges awaiting Mattis' successor Meet Trump's pick to take over the Joint Chiefs of Staff Retiring GOP lawmaker blasts Trump's threat to close border as 'angry eighth-grader’s tweet' MORE.

Midterm elections for sitting presidents are historically challenging. Democrats in the Senate are hoping to find some political momentum for 2018 given the difficult playing ground.  

Here are 10 Senate seats that could flip, in alphabetical order:

Bill NelsonClarence (Bill) William NelsonFight brews over felons’ voting rights in Florida Mellman: If only you couldn’t vote McCaskill: 'Too many embarrassing uncles' in the Senate MORE  (D-Fla.)

Democrats came into 2016 bullish about the Sunshine State.

But Republican incumbent Marco RubioMarco Antonio RubioNauert faces questions about qualifications at UN The Memo: Trump puts isolationism at center stage Trump's military moves accelerate GOP search for next McCain MORE’s decision to run for reelection cleared the muddled field and, ultimately, a surge in rural Republican voters outpaced Democrats’ gains in cities and with Hispanics. When the dust settled, Trump won by 1 percentage point, while Rubio held on to his seat by 8 points. 

Nelson, a three-term senator, is a well-known commodity in Florida, having held public office there since 1972. And he starts with a net 14-point approval rating, according to an October poll from Public Policy Polling. 

Possible challengers could include term-limited Gov. Rick Scott (R), a Trump ally, or any of the politicians who eyed the seat in 2016, including outgoing GOP Reps. David Jolly or Ron DeSantis.

Millionaire Carlos Beruff and Lt. Gov. Carlos Lopez-Cantera, both 2016 candidates, could also jump in. But the two are Scott allies, so it’s unlikely either would challenge the governor should he decide to run.

Joe DonnellyJoseph (Joe) Simon DonnellySenate approves funding bill, preventing partial government shutdown Hatch warns Senate 'in crisis' in farewell speech Dem senators Heitkamp, Donnelly urge bipartisanship in farewell speeches MORE (D-Ind.)

No state’s Senate race changed more in 2016 than Indiana’s. Republicans started the cycle looking likely to keep control of outgoing Sen. Dan CoatsDaniel (Dan) Ray CoatsIntel chief: Russia sought to influence Americans but did not compromise midterm elections Bottom Line Dems slam Trump for siding with Saudi Arabia in Khashoggi killing MORE’s seat with Democratic Rep. Barron Hill in the race. Then it seemed destined to go Democratic once Hill dropped out and former Sen. Evan Bayh jumped in. 

But a flurry of damaging stories and revelations stunted Bayh’s comeback, giving Rep. Todd YoungTodd Christopher YoungTrump's military moves accelerate GOP search for next McCain Kevin McLaughlin tapped to serve as NRSC executive director for 2020 Overnight Defense: Senate bucks Trump with Yemen war vote, resolution calling crown prince 'responsible' for Khashoggi killing | House briefing on Saudi Arabia fails to move needle | Inhofe casts doubt on Space Force MORE a 10-point win behind Trump’s 19-point victory. 

Donnelly seemed to have an uphill battle against Sen. Richard Lugar (R) in 2012, until the incumbent was toppled by former Indiana Treasurer Richard Mourdock.

Look for a much tighter race now, with potential GOP candidates such as Reps. Luke Messer, Susan BrooksSusan Wiant BrooksGOP rep says government needs to help telecom industry invest in 5G GOP struggles to find right Republican for Rules Here's how politicians celebrated Halloween MORE or Marlin Stutzman, who ran in the primary this past spring, in the mix.

Claire McCaskillClaire Conner McCaskillOcasio-Cortez responds to McCaskill: 'Pretty disappointing' McCaskill on Ocasio-Cortez: ‘I’m a little confused why she’s the thing’ McCaskill: GOP senators privately say Trump is ‘nuts’ MORE (D-Mo.)

Democrats are fresh off of a tight loss challenging Republican Sen. Roy BluntRoy Dean BluntElection agency prepares to tackle foreign interference Senate GOP: We need clarity from Trump on border demands Shutdown looms as Trump, GOP dig in on wall MORE’s reelection and now have to pivot to defending one of their own. Democrat Jason Kander fell to Blunt by 3 points, while Trump won the state by 19 points. 

McCaskill has won tough races before — she defeated incumbent Republican Sen. Jim Talent for her seat in 2008 and dispatched Rep. Todd Akin in 2012, a race that had been considered close until Akin’s infamous comment about “legitimate rape.”

Republicans will likely eye the red-state seat as a major pickup opportunity, potentially by one of the state’s six GOP lawmakers.

Jon TesterJonathan (Jon) TesterAfter 30 years, it’s time to rethink VA’s Cabinet department status Senators' last-minute demands may delay funding bill Senate votes to overturn IRS guidance limiting donor disclosure MORE (D-Mont.)

Tester steered the Democratic Senatorial Campaign Committee in 2016, so he’s led the party through its share of tough races. And winning as a Democrat in Montana is no easy feat.

Trump won the presidential vote by 21 points in Montana, but Gov. Steve Bullock (D) tapped into the state’s bipartisan leanings with his own 4-point win. 

GOP Rep. Ryan Zinke, the state’s only congressman, is seen as best positioned for a potential Tester challenge.

Dean HellerDean Arthur HellerTrump's most memorable insults and nicknames of 2018 Progressive strategist says changing demographics will help Dems House-passed stopgap measure in Senate limbo MORE (R-Nev.)

Nevada was one of the shining lights for Democrats up and down the ticket in 2016 — Clinton held the state by 2 points, the same margin that former state Attorney General Catherine Cortez Masto defeated Republican Rep. Joe Heck by to win the open Senate seat. 

That’ll give Democrats confidence coming into one of their few strong pickup opportunities of 2018. 

Look for the scramble to start right back up, with names like Rep. Dina Titus and retiring Sen. Harry ReidHarry Mason ReidRand Paul's Festivus 'grievances' include comparing Lindsey Graham to Senator Palpatine Durbin signals he will run for reelection Manchin’s likely senior role on key energy panel rankles progressives MORE’s son Rory leading the first round of speculation. 

Heidi HeitkampMary (Heidi) Kathryn HeitkampHirono will donate salary earned during government shutdown Murkowski to reintroduce bill to help abused Native American women Senate in last-minute talks to find deal to avert shutdown  MORE (D-N.D.)

North Dakota is another ruby-red state coming off a Republican blowout in 2016. Trump won by 36 points, Sen. John HoevenJohn Henry HoevenHirono will donate salary earned during government shutdown GOP lawmakers say Trump should tamp down trade rhetoric GOP nerves on edge after Sinema takes lead over McSally MORE won reelection by 62 points, and Republican Gov.-elect Doug Burgum won by 58 points. 

Rep. Kevin Cramer (R), the state’s only congressman, could entertain a bid against one of the Senate’s 21 women. 

Sherrod BrownSherrod Campbell BrownSherrod Brown seeks Obama meeting as he weighs 2020 run: report 2020 Dems go on offense over drug prices Five Democrats who could be dark horses in 2020 MORE (D-Ohio)

Brown’s populist streak has won him favor in Ohio for more than two decades, including two terms in the Senate, helping him win reelection in 2012 by 6 points. 

But Ohio took a sharp turn in the GOP’s direction in 2016, with Trump winning by 8 points, a larger margin than each of the past five presidential elections there. And Sen. Rob PortmanRobert (Rob) Jones PortmanIs Congress really that far behind on tech policy? No. Sens. Sanders and Feinstein oppose Israel anti-boycott provision John Kasich pitches soon to be shuttered Ohio GM plant to Elon Musk: ‘Call me’ MORE won by 21 points over his Democratic challenger, former Gov. Ted Strickland.

A term-limited Gov. John Kasich (R) could look to jump back to Congress, or state Treasurer Josh Mandel could look for a rematch against Brown, depending on who decides to run to replace Kasich. 

Bob CaseyRobert (Bob) Patrick CaseyWHIP LIST: Who’s in and out in the 2020 race Senators' last-minute demands may delay funding bill Would-be 2020 Dem candidates head for the exits MORE (D-Pa.) 

The Casey name has been in Pennsylvania politics for about a half-century, beginning with Casey’s father, who started in the state Senate in 1963 before stints as the auditor general and governor.

Casey has won big even in the tight state — he defeated incumbent GOP Sen. Rick Santorum by 18 points in 2006 and won reelection by 9 points in 2012. 

This year, GOP Sen. Pat Toomey won reelection by 2 points, bucking all the polls, and the electorate only stands to become more favorable for Republicans in an off year. 

Potential candidates could include two early Trump backers in Congress, Reps. 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 and Tom Marino, or others such as Rep. Pat Meehan. State Senate Majority Leader Jake Corman is another who could consider a bid, but many are in a holding pattern until Gov. Tom Wolf (D) decides whether he’ll seek reelection. 

Joe ManchinJoseph (Joe) ManchinRepublicans face 2020 repeat on health care Hillicon Valley: Trump DOJ charges Chinese hackers | House Intel to give Roger Stone transcript to Mueller | Senators lift hold on FCC commish | Slack deactivates Iran-linked accounts | Dem lawmaker calls on Facebook to fire Zuckerberg Senators lift hold on FCC commissioner MORE (D-W.Va.)

Manchin’s decision to run for reelection boosted the hopes of Democrats looking to hold the deep-red state.

Trump won the state by 42 points, but the Mountain State bucked the idea of voting straight ticket, electing Democratic coal executive Jim Justice to the governor’s mansion with a 7-point margin.

Republican state Attorney General Patrick Morrisey could consider a bid, as could GOP Reps. David McKinleyDavid Bennett McKinleyRepresenting patients’ voices Super PACs spend big in high-stakes midterms Twitter chief faces GOP anger over bias at hearing MORE, Alex Mooney or Evan Jenkins. 

Tammy BaldwinTammy Suzanne BaldwinDems say Trump is defying court order by pushing abstinence programs Dem senator accuses Wisconsin Republicans of 'power grab' Schumer reelected as Senate Democratic Leader MORE (D-Wis.)

The Wisconsin Republican infrastructure in the state helped Gov. Scott Walker win three elections in six years, including during the 2012 election that saw wins by both Baldwin and President Obama. 

Trump’s 1-point victory there, as well as Johnson’s comeback 3-point victory, gives Republicans hope to build on those margins with a midterm electorate. 

Walker is likely to run for reelection, but his lieutenant governor, Rebecca Kleefisch, could decide to go national. Rep. Sean DuffySean Patrick DuffyRare bipartisanship in lame duck Congress battling the ‘WTO’ of insurance regulation House votes to remove protections for gray wolves Here's how politicians celebrated Halloween MORE is another name mentioned as a potential Senate contender.