US Midterms 2018: Seven must-watch Senate races
Updated 23:08, 08-Nov-2018
By John Goodrich
["north america"]
The battle for the Senate has gathered plenty of attention ahead of Tuesday's US midterm elections, with Republicans in a strong position to hold on to the chamber.
35 seats are up for grabs, and the Republicans currently hold a slim 51-49 advantage. The Democrats only need two seats to take control of the chamber but the Republicans are in the box seat – they are defending nine seats and attacking 26.
FiveThirtyEight's latest forecast gives the Democrats a one-in-seven chance of winning control, and the Republicans six-in-seven chance of retaining a majority.
The latest update from The Cook Political Report shows four of the nine Republican-held seats are toss-ups, and five of the 26 Democrat-held seats fall into the same category.
With Heidi Heitkamp, the Democratic senator in North Dakota, having fallen well behind in her race, here are seven Senate battles to look out for on election night.  
- Republican Rick Scott, the 65-year-old incumbent governor, led the race until October but slipped behind as his opponent outspent him going into election day.  
- Democrat Bill Nelson, the incumbent senator, has edged into a polling lead in the final stretch of campaigning, but the 76-year-old's 1.7-point advantage is well within the margin of error.
- 2016: Trump 48.6%, Clinton 47.4%
Why it matters:
Florida is a key swing state, and the scene of an epic battle for the Senate seat currently held by Democrat Nelson. Outgoing governor Scott has served out his two-term limit and is trying his luck for a place in the Senate. Both men have name recognition, although Nelson is a little lower key, and turnout is likely to have been boosted by the high profile race for governor in the state. Flipping Florida would be a major boost for the Republicans, and the Democrats have little hope of taking control of the Senate unless they hold on. 
- Republican Ted Cruz, the 47-year-old incumbent senator, has consistently led the race but his lead has narrowed in the week before polling day.
- Democrat Beto O'Rourke is the fundraising superstar who has energized voters across the country, but for the 46-year-old to win in deep red Texas is a big ask and he trails by an average of around six points.
- 2016: Trump 52.2%, Clinton 43.2%
Why it matters:
The Texas race has had more national attention than any other thanks to the exploits of new Democratic star O'Rourke. His huge fundraising ability and cult following has made him the party's new pin-up, but in deep red Texas it may not be enough to beat former presidential candidate Cruz. The incumbent senator appears on course for victory, boosted by a rally held with one-time nemesis Trump, despite a narrowing of his lead in the final stretch. Win or lose, O'Rourke will be a name to watch as the Democratic spotlight switches to 2020.
- Republican Dean Heller, the 58-year-old incumbent senator, has come from behind to eke out a narrow polling lead in Nevada.
- Democrat Jacky Rosen trails by an average of 1.4 points going into polling day after the 61-year-old made a string of missteps on the campaign trail.
- 2016: Clinton 47.9%, Trump 45.5%
Why it matters:
Democrats were optimistic about flipping Nevada in what would be a huge fillip to their hopes of taking the Senate, but polls suggest Rosen has not had the impact the party hoped. Good news for Rosen came at the weekend with large crowds queuing to vote early in heavily Democratic Las Vegas, and in keeping with most Democrats this year she has out-fundraised her opponent. Heller is the only Republican senator contesting a state won by Clinton in 2016, and big name Democrats – from Obama to Sanders – have campaigned for Rosen. Holding Nevada would be big for the Republicans. 
- Republican Matt Rosendale, the 58-year-old state auditor, has made up ground but faced criticism for hailing from out of state and has relied heavily on surrogates.  
- Democrat Jon Tester, the incumbent senator, is known for his folksy, jovial style and the 62-year-old has a four-point average polling lead.
- 2016: Trump 56.5%, Clinton 36.0%
Why it matters:
Trump has been to Montana to stump for Rosendale and the local party has tried to make the race more about the president – who won the state by over 20 points – than the candidate. It's a revenge battle for Trump, after moderate Democrat Tester forced his pick to run the Veteran Affairs department to withdraw. Tester has a fundraising advantage, but holding on would still be a big result for the Democrats given the scale of Trump's victory in the state.  
- Republican Martha McSally, a former Air Force colonel, has slipped behind in the polling average with 46.4 percent but the 52-year-old leads in several individual polls.
- Democrat Kyrsten Sinema, a 42-year-old two-term congresswoman, surged ahead in the average of polls last week and has an average 1.9-point polling lead.
- 2016: Trump 48.1%, Clinton 44.6%
Why it matters:
Republican Senator Jeff Flake decided not to run again in Arizona, fearing that his traditional conservatism would lose out in a primary contest in the Trump era. Flake, who may yet contest the presidency in 2020, won the seat in 2012 by three points but the more extreme McSally is in a tighter race with Sinema. The Democrat has cast herself as a centrist, and campaigned relentlessly on healthcare and education. McSally has had the backing of Trump, has attacked Sinema as dangerously liberal and supported Obamacare repeal. Arizona is one of the Democrat's best opportunities to flip a seat.
- Republican Josh Hawley is the marginal favorite going into election day, with the 38-year-old state attorney-general holding a 1.4-point lead in a polling average.
- Democrat Claire McCaskill, the incumbent senator, remains within striking distance but the 65-year-old is the underdog heading into Tuesday. 
- 2016: Trump 56.4 %, Clinton 37.9%
Why it matters:
One of the closest races in the country is expected to go to the wire, with McCaskill fighting the odds to win a third term. Trump won the state by a massive 18.5 points in 2016 and is scheduled to make a campaign appearance just hours before polls open as the Republicans aim to flip the state. McCaskill voted against the nomination of Brett Kavanaugh as a Supreme Court justice, an issue Hawley has repeatedly attacked her on and one which Republicans believe may have swung the race their way. 
- Republican Mike Brawn was a surprise primary pick, but the 64-year-old businessman's lack of political experience allowed him to cast himself as an outsider.  
- Democrat Joe Donnelly is one of the most at-risk incumbent Democrats, and the 63-year-old is clinging to an average 1.2-point lead going into polling day.
- 2016: Trump 56.5%, Clinton 37.5%
Why it matters:
Indiana voted heavily for Donald Trump in 2016 and holding on to his Senate seat always looked tough for Democrat Donnelly, who won in 2012 against an error-prone candidate. Donnelly decided to vote against the nomination of Brett Kavanaugh as a Supreme Court justice, potentially alienating undecideds who tend to lean Republican in the state. Taking back Indiana wouldn't be a shock for the Republicans, but it would be a big blow for the Democrats. 
(Graphics by Zhao Hong and Yu Peng)