9 Senate races that are shaping up to be nail-biters and will determine which party controls the Senate

The US Senate candidate Rep. Beto O’Rourke, a Texas Democrat. Chip Somodevilla/Getty Images
  • Control of the Senate will be determined in Tuesday’s US midterm elections – and several races could go either way.
  • While pollsters predict Democrats will flip the House, they say chances are much slimmer that the “blue wave” will reach the Senate.
  • Here are nine Senate races to keep an eye on.

Control of the Senate will be determined in Tuesday’s midterm elections – and there are several very competitive races to watch.

Democratic incumbents in 10 states that President Donald Trump won in 2016 are facing tough reelection contests. Democrats are also facing uphill battles in red states where they hope to pick up seats, including Arizona, Nevada, Texas, and Tennessee.

Nate Silver of FiveThirtyEight predicted on Thursday that Democrats had a 15% chance of flipping the Senate and asserted that Democrats would need “some type of systematic polling error to win the Senate.”

While Democratic leadership remains bullish on flipping the upper chamber, many operatives are less optimistic. And Trump declared last week that the so-called Democratic blue wave was “dead,” expressing confidence that the GOP would maintain its hold on the Senate.

“I think we’re doing very well … I think we’ll win the Senate, and I think we’re gonna do well on the House,” Trump told the Christian Broadcasting Network on Wednesday.

Read more:
SENATE BATTLEGROUND MAP: The race for control of the Senate is tight

Here are the 9 most competitive Senate races to watch:

North Dakota: Democratic Sen. Heidi Heitkamp versus GOP Rep. Kevin Cramer

Heitkamp was elected to the Senate with just 3,000 more votes than her opponent. And her reelection battle is shaping up to be just as tight, with the odds in Cramer’s favour.

Heitkamp hasn’t led a poll since February, and her decision to vote against Brett Kavanaugh’s Supreme Court confirmation may have hurt her.

A recent Fox News poll had Cramer leading Heitkamp 51% to 42% among likely voters. And the nonpartisan Cook Political Report recently moved the race to its “Lean Republican” category.

Arizona: Republican Rep. Martha McSally versus Democratic Rep. Kyrsten Sinema

McSally and Sinema are locked in a very close race to fill the retiring Republican Sen. Jeff Flake’s seat as the number of undecided voters in the purple state has dropped.

A recent Fox News poll had both at 46% support among lightly voters, and a recent CNN poll had Sinema up over McSally 51% to 47% – a lead within the poll’s margin of error.

Missouri: Democratic Sen. Claire McCaskill versus Attorney General Josh Hawley

McCaskill was tied with Missouri’s Republican attorney general, Hawley, in a recent Fox News poll.

Trump won the deeply red state by nearly 19 points in 2016, and, evidencing her desperation, McCaskill has tried to distance herself from more left-leaning members of her party, insisting in a late-October radio ad that she’s “not one of those crazy Democrats.”

Nevada: Republican Sen. Dean Heller versus Rep. Jacky Rosen


A recent CNN poll had Rosen up by 3 percentage points over Heller, well within the margin of error. Still, the same poll found Trump’s approval rating rising 4 points, to 49%, from the previous survey among likely voters in the key swing state.

Texas: Republican Sen. Ted Cruz versus Democratic Rep. Beto O’Rourke

In a race on which the entire nation seems to be hyperfocused, O’Rourke is giving Cruz, a 2016 presidential contender, a real run for his money.

A few indicators are pointing in the Democrat’s direction: O’Rourke has raised more money than any Senate candidate in history – with no help from corporate PACs – and early voting particularly among millennials is way up.

But Texas is a deeply red state, and recent polls have Cruz ahead of O’Rourke. An Emerson College poll released Thursday showed Cruz up by just 3 points, within the margin of error.

Tennessee: Republican Rep. Marsha Blackburn versus Democratic former Gov. Phil Bredesen


Tennessee – a state Trump won by 26 points – is seeing an unexpectedly tight race to replace the retiring GOP Sen. Bob Corker.

Bredesen, the state’s popular former two-term governor who also once served as mayor of Nashville, is running against Blackburn, a conservative hard-liner who has Trump’s strong endorsement.

A recent Fox News poll had Blackburn leading Bredesen by 8 points among registered voters – a jump from the 6-point lead she had in the same poll in September.

Read more:
A Democratic campaign that looks nothing like the ‘resistance’ could be the Democrats’ key to flipping the Senate

Montana: Democratic Sen. Jon Tester versus Republican Matt Rosendale

Tester. Tasos Katopodis/Getty Images

Tester is locked in a relatively tight battle with Rosendale, Montana’s state auditor. A poll released by the nonpartisan group Gravis Marketing on Tuesday had Tester up by 3 points.

Tester has never won 50% of the vote in his red state, and Republicans hope the president’s rallies – and Donald Trump Jr.’s multiple trips to Big Sky country – will help boost GOP enthusiasm.

Florida: Democratic Sen. Bill Nelson versus Republican Gov. Rick Scott

Nelson had a slight 2-point lead over Scott among likely voters in a poll by Suffolk University with USA Today, well within the margin of error.

But Scott is suffering from low favorability in the Sunshine State, with 45% of likely voters in the poll disapproving of his job as governor.

Indiana: Democratic Sen. Joe Donnelly versus Republican Mike Braun

A recent poll by NBC News and Marist found Donnelly ahead of Braun by 2 points, well within the margin of error, in a state Trump won by 19 points.