This year is shaping up to be one of the closest years for elections in a long time. These states will decide who may make up a majority in the Senate. In no particular order, here are those races by state.
Arizona: Rep. Martha McSally vs. Rep. Kyrsten Sinema
Representative Martha McSally
The closest race in Arizona is for the seat to replace current U.S. Senator Jeff Flake. This seat will be crucial in determining the composition of the United States Senate. The candidates are Rep. Martha McSally, a former Air Force Colonel, and Rep. Kyrsten Sinema, a former member of the Arizona Legislature. McSally was a critic of President Trump in 2016 but now has embraced him with open arms. Sinema, a former member of the Green Party, is one of the Democrats who votes in line with President Trump most of the time. This race is sure to be contentious, and all eyes are watching to see if the seat held by a Republican for the last 23 years will turn blue for the Democrats.
Nevada: Sen. Dean Heller vs. Rep. Jacky Rosen
Representative Jacky Rosen
The only Republican incumbent running in a state won by Hillary Clinton is Senator Dean Heller. Heller has campaigned against the Affordable Care Act, and is seen as the most vulnerable Republican incumbent senator in the U.S. He narrowly won his seat back in 2012 by a meager 11,576 votes. His opponent, Rep. Jacky Rosen is running neck and neck with Heller throughout the state. While Rosen is seen as the best candidate to replace the current incumbent, 16% of likely voters in Nevada have never heard of Rosen. They both have work to do as election day nears.
Missouri: Sen. Claire McCaskill vs. Atty. Gen. Josh Hawley
Attorney General Josh Hawley
Claire McCaskill has represented Missouri in the Senate for 12 years. Many say she is the most vulnerable Democratic incumbent senator. Her challenger, the Attorney General of Missouri, Josh Hawley, has been scandal-ridden since the beginning of his campaign. His former Governor, Eric Greitens, was involved in a sex scandal that has followed Hawley's campaign and hindered his ability to win over the trust of some key voters. Hawley finally received some relief when the Governor resigned, and thus allowed him to cruise to victory in the primary. McCaskill is trying to appeal to rural voters, who voted for Trump back in 2016. She has modified her message to emphasize her ability to work across the aisle to make sure the Missouri voters do not see her as too liberal. Without the shadow of Greitens hanging over him, Hawley focuses on attacking McCaskill from now until November, but she has shown that she can attack him right back.
Tennessee: Rep. Marsha Blackburn vs. Fmr. Gov. Phil Bredesen
Representative Marsha Blackburn
Former Democratic Governor Phil Bredesen is trying to make a comeback in Tennessee. Bredesen has not run in an election since 2006. He won every county in that election and captured 68% of the vote. He is extremely popular in the state, even the outgoing Senator, Bob Corker, approves of him. On the Republican side is Marsha Blackburn. Blackburn has been a representative since 2002 and has been a vocal supporter of President Trump. Bredesen is largely known throughout the state, whereas Blackburn has to work harder to let people know who she is. This race is a toss-up and is sure to be close.
North Dakota: Sen. Heidi Keitkamp vs. Rep. Kevin Cramer
Senator Heidi Heitkamp
The challenger, rep. Kevin Cramer, had toyed with running several times. He changed his mind twice, but with encouragement from Washington, he is officially in. Senator Heitkamp is also among the most vulnerable as she only won her last election by one point. In a state that is moving more and more to the right, the odds are not in her favor. Cramer has aligned himself with President Trump on most issues, which may be a positive since Trump won that state with 63% of the vote. Heitkamp is emphasizing her independent position where she is not too liberal on particular issues. There may be some hope for Heitkamp though. The approval rating for President Trump in North Dakota has been dropping, which may shift the enthusiasm into her hands.
Indiana: Sen. Joe Donnelly vs. Mike Braun
Senator Joe Donnelly
The Hoosier state voted for Trump and former Indiana Governor Mike Pence 56-38. His approval rating is sitting just about 50% right now, which may be a good sign for the Republican running in this race, Mike Braun. Braun is a staunch conservative who supports Trump almost all the way. Donnelly, on the other hand, is only a Democrat when he needs to be. This helps Donnelly in Indiana, considering the state has gotten more and more conservative over the years. Donnelly is another vulnerable Democrat in a reliable red state, this race will probably go late into the night.