While the Democratic Party hopes to capitalize on its victory in the Alabama special election to win back control of the Senate, the sheer number of seats they must defend, especially in states won by President Trump in 2016, makes the prospect of wresting back control of the Senate a significant challenge at best.
Heading into the 2018 midterms, Republicans hold a slim 51-47 majority, with two seats held by independents who caucus with the Democrats. Democrats are poised to defend 25 seats (including both independents), while Republicans must defend eight.
While the lopsided number of contested seats held by Democrats compared to those held by Republicans is a tough enough obstacle for Democrats to overcome, they are further burdened by having to defend ten seats in states won by President Trump in 2016.
In sharp contrast, Republicans are defending only one seat in a state won by Hillary Clinton.
Despite there being 33 Senate seats up for re-election this year, control of the chamber will be decided by less than 15 key races.
Arizona (Toss-Up, Retiring Republican Incumbent)
Republican Senator Jeff Flake, a staunch opponent of President Trump, announced he will not seek re-election. While no Democrat has represented Arizona in the Senate for over 20 years, shifting demographics make the state one of the Democrats’ best opportunities for a pickup.
Democrats are rallying behind Representative Kyrsten Sinema, who is openly bisexual and a self-described atheist. Sinema represents Arizona’s 9th Congressional District.
The Republican primary is set to be a bruising battle between the party establishment, in the form of Representative Martha McSally, and populist outsiders, most notably former Maricopa County Sheriff Joe Arpaio and former State Senator Kelli Ward, who unsuccessfully challenged Senator John McCain in the 2016 Republican primary.
While Trump won Arizona by nearly 3.5 percent, it was a sizable decline from Mitt Romney’s 9 percent margin of victory over Obama in 2012, demonstrating the state’s shift towards the Democratic Party in the face of a rapidly growing Hispanic population.
Florida (Toss-Up, Democratic Incumbent Seeking Re-Election)
Incumbent Senator Bill Nelson is one of ten Democrats seeking re-election in a state won by President Trump. While Nelson handily won re-election in 2012, he is now the only Democrat to hold statewide office.
While numerous Republicans have already declared their candidacies, most are holding out hope that term-limited Governor Rick Scott enters the race. Early polls show Scott tied with Nelson, or leading outright.
Indiana (Toss-Up, Democratic Incumbent Seeking Re-Election)
Senator Joe Donnelly is another Democrat unfortunate enough to be running for re-election in a state handily won by President Trump, making Indiana one of the Republican Party’s best opportunities to flip a seat.
The two top candidates vying for the Republican nomination are Representatives Luke Messer and Todd Rokita.
Maine (Leans Independent, Incumbent Independent Seeking Re-Election)
Senator Angus King, an independent who caucuses with the Democrats, is running for re-election in a state Hillary Clinton carried by around three percent.
While the only declared Republican candidate thus far is State Senator Eric Brakey, who has been endorsed by Kentucky Senator Rand Paul and former Texas Representative Ron Paul, President Trump has reportedly urged outgoing Governor Paul LePage to toss his hat into the race.
Missouri (Toss-Up, Democratic Incumbent Seeking Re-Election)
President Trump carried Missouri by over 18 percent in 2016, leaving incumbent Senator Claire McCaskill incredibly vulnerable as she seeks re-election. McCaskill’s re-election campaign in 2012 was the last time a Democrat won statewide office in Missouri.
Republicans are rallying around State Attorney General Josh Hawley, who will face numerous candidates in the primary, including Austin Petersen- a failed candidate for the Libertarian Party’s nomination for president in 2016.
Montana (Lean Democratic, Incumbent Democrat Seeking Re-Election)
Democratic Senator Jon Tester is running for re-election in a state President Trump carried by over 20 percent, making Montana a prime target for Republicans.
Tester, who won his first term by one percent and his second term in 2012 by less than four percent, has already attracted a large field of Republican challengers, including State Auditor Matt Rosendale, businessman Troy Downing, and State Senator Albert Olszewski.
Nevada (Toss-Up, Republican Incumbent Seeking Re-Election)
Republican Senator Dean Heller has the dubious distinction of being the only Republican running for re-election in a state won by Hillary Clinton. Shifting demographics have turned the once purplish-red state blue, making Nevada one of the Democratic Party’s most opportune pick-ups.
First-term Representative Jacky Rosen and attorney Jesse Sbaih are the top two Democratic candidates.
Heller, who won his first term in 2012 by less than one percent, must first get through his party’s primary, where he faces insurgent populist candidate Danny Tarkanian.
North Dakota (Leans Democratic, Incumbent Democrat Seeking Re-Election)
President Trump won North Dakota by a staggering 35.7 percent, leaving Democratic Senator Heidi Heitkamp vulnerable as she seeks re-election. Despite her vulnerability, however, no high-profile Republican has declared their candidacy as of yet.
State Senator Tom Campbell is the only declared candidate thus far after the state’s at-large Representative Kevin Cramer announced he will not enter the race. Former Representative Rick Berg, who lost to Heitkamp by less than one percent in 2012, could also enter the race.
Ohio (Leans Democratic, Incumbent Democrat Seeking Re-Election)
After being labeled a toss-up throughout the 2016 presidential campaign, President Trump went on to carry the Buckeye State by over eight percent. The state’s incumbent Senator, Sherrod Brown, is now Ohio’s sole Democrat elected to statewide office.
The previous Republican front runner, State Treasurer Josh Mandel, recently dropped out of the race citing his wife’s health, leaving the party without a high-profile candidate until Representative Jim Renacci entered the race.
Renacci previously declared his intention to run for Governor to replace term-limited John Kasich.
Pennsylvania (Leans Democratic, Incumbent Democrat Seeking Re-Election)
President Trump pulled off an upset when he defeated Hillary Clinton in Pennsylvania, leaving incumbent Democratic Senator Bob Casey vulnerable.
Representative Lou Barletta is the font-runner for the Republican nomination.
Tennessee (Leans Republican, Incumbent Republican Retiring)
Tennessee Senator Bob Corker, who transitioned from an ally of President Trump to one of his harshest critics, announced he will not seek re-election.
Democrats, using their special election victory in Alabama as justification, believe they can flip Tennessee after former Governor Phil Bredesen announced his candidacy.
Representative Marsha Blackburn is the likely Republican candidate.
West Virginia (Toss-Up, Democratic Incumbent Seeking Re-Election)
West Virginia gave President Trump his largest margin of victory over Hillary Clinton (42.2 percent), leaving Senator Joe Manchin incredibly vulnerable.
The Republican primary will feature another battle between the party establishment’s preferred candidate, Representative Evan Jenkins, and the populist wing, represented by State Attorney General Patrick Morrisey.
Safe Democratic Seats
Despite being forced to defend 25 seats this year, many are in states that are solidly Democratic politically.
Apart from Senator King in Maine, the Democratic Party’s other Senators in the northeast, namely Bernie Sanders of Vermont, Elizabeth Warren of Massachusetts, Chris Murphy of Connecticut, Sheldon Whitehouse of Rhode Island, and Kirsten Gillibrand of New York are all safe bets to win re-election.
Hillary Clinton’s running mate, Virginia Senator Tim Kaine, is secure in his re-election campaign, as are fellow mid-Atlantic Senators Tom Carper of Delaware and Ben Cardin of Maryland. Despite his legal troubles, New Jersey Senator Bob Menendez is all but certain to be re-elected as well.
While President Trump won parts of the Rust Belt, Minnesota’s two Senate seats are all but certain to remain Democratic. Incumbent Senator Amy Klobuchar’s coattails will likely provide Tina Smith, who was appointed to fill the seat after Al Franken resigned in disgrace, enough of a boost to win her special election.
Despite Trump’s victories in Michigan and Wisconsin, Senators Debbie Stabenow and Tammy Baldwin are very likely to win re-election.
In keeping with the state’s Democratic tilt, New Mexico Senator Martin Heinrich will cruise to re-election.
On the West Coast, California Senator Dianne Feinstein is safe, provided she defeats her likely opponent in the general election: State Senate President Kevin de Leon. Washington Senator Maria Cantwell and Hawaii Senator Mazie Hirono are also safe.
Safe Republican Seats
Mississippi Senator Roger Wicker is certain to win re-election, provided he survives a possible primary challenge from State Senator Chris McDaniel, who came close to unseating the state’s other Republican Senator, Thad Cochran, in 2014.
Senator Deb Fischer of Nebraska is a shew-in to win re-election in a state President Trump carried by 25 percent.
While Texas Senator Ted Cruz is all but certain to win re-election, the margin of victory will be an indication of how far the Democratic effort to turn the Lone Star State blue has progressed.
Utah Senator Orrin Hatch’s decision to retire likely made the seat more likely to remain in Republican hands, with former Massachusetts Governor Mitt Romney being the front runner. Nearby, Wyoming Senator John Barrasso is also safe.