effect on leadership of Capitol Hill defense committees.
This year, that group includes the Arizona Senate race, with Republican John McCain expected to win re-election, and the departures of several high-profile House Armed Services Committee members.
But dozens of other races will influence which party sets that agenda, and who will be on the team that writes the annual defense budget bills for the next few years.
Here are four races to watch on election night that could have long-reaching effects on military and veterans issues:
MISSOURI SENATE
Republican incumbent Sen. Roy Blunt was expected to easily win re-election when his campaign began last year, but his Democratic challenger — Missouri Secretary of State Jason Kander — has turned the race into a toss-up by painting Blunt as a Washington insider who has forgotten his constituents.
Kander, a former Army captain who served in Afghanistan, has touted his military experience on the campaign trail, and drew national headlines for an ad where he talks about gun control while assembling an AR-15 blindfolded.
The race is one of eight toss-up Senate races that could determine political control of the chamber, and has drawn significant interest from veterans groups. The progressive group VoteVets.org had previously put $1.5 million into getting Kander elected, and last week added another $1 million in last-minute spending.
A Kander victory could be a signal of a Democratic wave on election night, and a new defense voice on Capitol Hill for his party.
ARIZONA'S 2ND HOUSE DISTRICT
Republican incumbent Rep. Martha McSally lost an election bid for her southeastern Arizona district by just a few hundred votes in 2012, and won the seat in 2014 by less than 200 votes. Her contest this year against Democratic challenger Matt Heinz looks to be close again.
McSally, a former A-10 pilot who flew missions over Iraq and Afghanistan, has become a headache for Air Force officials over the that aircraft, helping to lead opposition of retirement plans for the close-air support plane. She has argued that replacement F-35 aircraft are too costly and won’t perform as well in specialized support missions.
That opposition will continue in Congress regardless of how McSally’s re-election bid turns out.
But a loss by McSally will ease some of that pressure on the Pentagon.
COLORADO'S 6TH HOUSE DISTRICT
Republican incumbent Mike Coffman has held his eastern Denver district since 2009 despite a few close campaigns. Now the Iraq War veteran faces his most difficult re-election bid yet against Democratic State Sen. Morgan Carroll.
Coffman has become an influential player on the House Armed Services Committee and the House Veterans’ Affairs Committee, where he has attacked Department of Veterans Affairs leaders repeatedly for inefficiency and incompetence. At times that has included angry sparring with VA Secretary Bob McDonald in public hearings that has shocked many within the veterans community.
Republicans need Coffman, like McSally, to find a way to hold onto their seats to prevent a possible Democratic takeover of the House. But current polls have Coffman and Carroll in a dead heat, with the presidential race potentially tipping the scales on voter turnout and attitudes.
FLORIDA'S 18TH HOUSE DISTRICT
Republicans are expected to see their majority in the House shrink considerably on Tuesday, but one district they’re hoping to flip from Democratic control is that of Rep. Patrick Murphy, who is running against incumbent Republican Sen. Marco Rubio.
Their pick to pull the district away from Democratic hopeful Randy Perkins, a businessman largely self-funding his bid, is Army veteran Brian Mast, a former bomb technician who lost both legs attempting to defuse an improvised explosive device in Afghanistan in 2010.
Foreign policy has crept into the local race, with Mast emphasizing the need to fight terrorist threats worldwide and saying he is open to sending more troops into Iraq. Murphy’s predecessor in the seat was controversial Republican Allen West, who used his foreign policy credentials and status as an Army lieutenant colonel to win the post in 2010.