National security hasn’t been at the forefront of the 2020 congressional campaigns, but the election results could have a significant impact on defense and foreign policy decisions on Capitol Hill next year.

In addition to the possibility that control of the White House and Senate could change parties, several prominent members of Congress up for re-election this cycle face difficult contests. Their victories or defeat could help reshape their party’s messaging on military spending, overseas deployments and a host of other issues within the Defense Department.

Here are five of the most noteworthy races for defense advocates to keep an eye on:

Iowa Republican Sen. Joni Ernst

Just a few years ago, Ernst was seen as a potential Republican fixture on the Senate Armed Services Committee for decades. Now, she’s in a close re-election fight that could force her to leave the Senate after a single term.

Ernst, 50, is a former Iowa National Guardsman who became the first female combat veteran elected to the chamber. She was elected vice chairman of the Senate Republican Conference in 2018 and has been a major voice for her party on military personnel and counterterrorism issues.

She was also rumored to be a potential vice president pick for President Donald Trump in 2016. But dissatisfaction with the president and Ernst’s Republican resume have hurt her this election cycle, with the latest Iowa polls calling the race a toss-up.

“Ernst is in a fight for her political life that I think six months ago, none of us were expecting,” said Jacob Rubashkin, an analyst with Inside Elections.

If Republicans hope to retain control of the committee and the chamber, her race is a near must-win. If she loses, her party loses not only that political advantage but also a key figure in their long-term defense policy plans.

Michigan Democratic Rep. Elissa Slotkin

Like Ernst, Slotkin is seen as a young leader within her party on defense and national security issues. Unlike Ernst, her path to re-election looks more secure, with a small but significant lead in recent polls.

But if Slotkin struggles — or loses — it will signal that Democrats won’t perform as well this election cycle as they hoped.

Slotkin, 44, is a former Central Intelligence Agency analyst and Department of Defense policy official who has carved out a vocal role on the House Armed Services Committee. Along with other swing district members, she has worked to pull her party closer to centrist positions on a host of issues, arguing that lawmakers must better balance military budget needs with other domestic priorities.

A re-election win puts her in line for larger leadership roles in the caucus on defense issues. A loss may force the party to reassess their approach to numerous districts across the country.

Georgia Republican Sen. David Perdue

Only a few Democrats on the Senate Armed Services Committee have tough re-election fights this cycle. Sen. Doug Jones is widely viewed as the underdog in his bid to return as the senator from heavily Republican Alabama. Michigan Sen. Gary Peters has seen some opposition in his contest but is still favored to win.

Republicans on the committee, however, face a more daunting task. Along with Ernst, several incumbents face election showdowns that could be decided by just a few thousand votes.

Arizona Sen. Martha McSally is projected by pollsters to lose her seat. North Carolina Sen. Thom Tillis, chairman of the personnel subcommittee, and Alaska Sen. Dan Sullivan, chairman of the readiness subcommittee, are both in close contests in states once believed firmly in Republican control.

The bellwether of the group may be Perdue, chairman of the seapower subcommittee. He won his 2014 election bid by about 8 percent of the vote but has been deadlocked in the polls with Democratic challenger Jon Ossoff.

Georgia Democrats haven’t managed a close race in Senate campaigns for the last 24 years, when Max Cleland won his seat by less than 2 percent of the state vote.

If Ossoff or Perdue can get 50 percent of the vote after Tuesday’s votes are counted, they’ll win the seat outright. If not, the race will go to a Jan. 5 run-off contest, one that could determine political control of the entire Senate.

“Republicans often have a turnout edge in such races in Georgia,” wrote Kyle Kondik, managing editor of Sabato’s Crystal Ball. “But we really can’t rule out Ossoff winning on Election Day — or winning the runoff depending on the circumstances.”

Ohio Republican Rep. Mike Turner

Turner, a defense spending advocate and the ranking member of the House Armed Services' Strategic Forces Subcommittee, faces an unusually competitive race against a young, well-funded Democratic challenger, Desiree Tims.

Turner is leading in the polls, but with a margin of victory much smaller than the usual 20-plus percent he has seen in past contact. Democratic Party officials have put significant backing behind Tims, forcing Turner to spend more time and money in the race than his supporters are used to.

The fight comes as Turner eyes succeeding retiring House Armed Services Committee ranking member Mac Thornberry, R-Texas, in that leadership role. If Turner loses, or if the race weakens internal GOP views of Turner’s standing, it could hurt his chances for that post.

Pollsters say Biden could perform well in the district, which covers Wright-Patterson Air Force Base and working-class Dayton. But even with that, Tims likely faces a slim opportunity for an upset win.

“Turner is such an institution that I have a hard time seeing him actually losing,” said Kondik. “That would be a pretty big surprise.”

South Carolina Republican Lindsey Graham

Graham hasn’t been a member of the Senate Armed Services Committee for several years but remains a key foreign policy voice in Congress and a sounding board for Trump on overseas deployments and military engagements.

Graham, a former Air Force legal officer, has also become a lightning rod for controversy in recent years because of his public defense of Trump and his role as Senate Judiciary Committee Chairman, where he recently oversaw the confirmation of Amy Coney Barrett to the Supreme Court.

He hasn’t faced serious opposition in any of his previous Senate campaigns, winning each by at least 10 percent of the vote. But this year’s contest against Democrat Jamie Harrison has proven more difficult, with some polls showing Graham trailing among likely voters.

A major anti-Trump wave among voters this cycle could force Graham out of office, handing control of the chamber to Democrats and removing Graham as a prominent party voice on national security.

Leo covers Congress, Veterans Affairs and the White House for Military Times. He has covered Washington, D.C. since 2004, focusing on military personnel and veterans policies. His work has earned numerous honors, including a 2009 Polk award, a 2010 National Headliner Award, the IAVA Leadership in Journalism award and the VFW News Media award.

Joe Gould was the senior Pentagon reporter for Defense News, covering the intersection of national security policy, politics and the defense industry. He had previously served as Congress reporter.

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