Republican Josh Hawley unseats incumbent Democratic Sen. Claire McCaskill in highly contested Missouri race

Jeff Roberson/AP

Republican Senate candidate Josh Hawley waves to the crowd after being introduced by President Donald Trump during a campaign rally Monday, Nov. 5, 2018, in Cape Girardeau, Mo.

• Republican state attorney general Josh Hawley won a Senate seat in Missouri on Tuesday following a highly contested race against Democratic incumbent Claire McCaskill.
• The race was one of the most closely watched contests of the 2018 midterm election season, and a RealClearPolitics average of the most recent polls had McCaskill and Hawley in a dead heat.
• McCaskill campaigned by painting herself as independent from mainstream Democratic thinking and true to Missouri values, while Hawley aligned himself closely with President Donald Trump.

Republican attorney general Josh Hawley won a highly contested race for a Senate seat in Missouri following Tuesday's midterm elections, unseating Democratic incumbent Claire McCaskill.

The race between Hawley and McCaskill was one of the most closely watched contests of the 2018 election season. A RealClearPolitics average of the most recent polls had the two candidates in a dead heat, at 46% each. And according to RealClearPolitics polling data, neither candidate has had a lead of more than four points in any poll over the whole year, which places the race within the margin of error.

President Donald Trump campaigned hard for Hawley in recent days - he held two rallies in Missouri to boost support for the Republican attorney general. While McCaskill has painted herself as independent from mainstream Democratic thinking in an effort to draw more undecided voters, Hawley has aligned himself closely with the president in order to draw more support from the Republican base.

Two key issues that Republicans are seizing on going into the midterms are the migrant caravan from Honduras headed toward the US's southern border, and the confirmation of Supreme Court Justice Brett Kavanaugh. Hawley and Trump have focused, in particular, on McCaskill's vote against Kavanaugh to portray her as a hardline Democrat.

McCaskill was first elected to the Senate in 2006, when she defeated Missouri Republican incumbent Jim Talent. In 2012, it looked like McCaskill may lose her seat to her Republican opponent, GOP Rep. Todd Akin, until he claimed in an interview that a woman could not get pregnant as a result of a "legitimate rape."

This year, McCaskill faced more of an uphill battle, particularly in a state that Trump won by 20 points in the 2016 US presidential election.