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The 10 Most Vulnerable Senators on Election Day

Minnesota’s Tina Smith debuts on list as Wisconsin’s Tammy Baldwin drops off

For the third month in a row, North Dakota Sen. Heidi Heitkamp tops the list of Senate incumbents most likely to lose on Nov. 6. (Tom Williams/CQ Roll Call file photo)
For the third month in a row, North Dakota Sen. Heidi Heitkamp tops the list of Senate incumbents most likely to lose on Nov. 6. (Tom Williams/CQ Roll Call file photo)

Democrats continue to dominate Roll Call’s list of the year’s most vulnerable senators, but one Democrat in a state President Donald Trump won has fallen off since our last rankings a month ago. 

Wisconsin Sen. Tammy Baldwin is no longer in the Top 10, with operatives on both sides noting the Badger State contest has been slipping away from Republicans. With Baldwin dropping off, Texas Republican Ted Cruz and New Jersey Democrat Robert Menendez move up, although both are still favored to win re-election.

A new addition to the list is Sen. Tina Smith, a Minnesota Democrat who’s running in a special election to fill out the remainder of former Sen. Al Franken’s term less than a year after she was appointed to the seat.

[The 10 Most Vulnerable House Incumbents on Election Day]

Democratic Sen. Heidi Heitkamp of North Dakota, still facing a tough race in a GOP-leaning state, remains in the top spot. Her other vulnerable party colleagues in states Trump won by double digits also stay put, including Missouri’s Claire McCaskill (No. 3) and Indiana’s Joe Donnelly (No. 4). The highest-ranked Republican on the list is Sen. Dean Heller of Nevada, who again comes in second. 

The rankings are based on conversations with strategists from both sides of the aisle, polling, and the race ratings from Inside Elections with Nathan L. Gonzales. We look solely at vulnerable incumbents and do not include open seats that are likely to flip.

Watch: 25 Race Ratings Changes Less Than a Week Before Midterms

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1. Heidi Heitkamp, D-N.D. 

The broader dynamics of a GOP-leaning state are working against the first-term senator and in favor of her Republican opponent, Rep. Kevin Cramer. That’s especially the case after Heitkamp voted not to confirm Brett M. Kavanaugh to the Supreme Court. But the high court fight energized both sides, and Democrats say the incumbent’s strength as a candidate and fundraising advantage shouldn’t be discounted. North Dakota remains a red state, though, with Heitkamp the only remaining member of her party in statewide elected office.

Race Rating: Leans Republican

2. Dean Heller, R-Nev.

Heller has never lost a race in his long political career. But as the only GOP senator running for re-election in a state that Hillary Clinton won in 2016, he’s still the most vulnerable Republican. He’s locked in a tight race with Democratic Rep. Jacky Rosen, who has held a slight edge in some recent public polling (in a state where Democrats believe their voters are often undersampled in surveys). With the national environment also likely to bolster Rosen and early ballot returns favoring Democrats, Heller stays near the top of the list.

Race Rating: Tilts Democratic

3. Claire McCaskill, D-Mo.

Republicans feel the race to unseat McCaskill is starting to move in their direction. Missouri Attorney General Josh Hawley has focused much of his campaign on the push for conservative judges. McCaskill has pressed Hawley on health care, particularly on protections for people with pre-existing conditions. Trump is traveling to Missouri on Monday to try and boost Republicans in a state he won by 19 points in 2016.

Race Rating: Tilts Republican

4. Joe Donnelly, D-Ind.

This race has tightened in favor of GOP nominee Mike Braun over the last month. Several factors are at play here, only one of which may be the Kavanaugh effect. (Donnelly voted against confirming the Supreme Court justice, likely losing support among some GOP and independent voters.) While some Republicans may have naturally come home, Braun has also finally put more of his own money into the race and seems to have stepped harder on the gas after running a lackluster campaign for much of the summer. Still, Donnelly is running close to Trump in a state the president carried by nearly 20 points, and Democrats are continuing to go after Braun over his business record and health care.

Race Rating: Toss-up

5. Bill Nelson, D-Fla. 

While the outlook for many Democrats running in Trump states has worsened this fall, Nelson’s odds seem to have improved over the past couple of months. He remains at No. 5, just where he was in October. Florida is more Democratic than most states on this list, which is why outside groups have been attacking the GOP nominee, Gov. Rick Scott, by tying him to Trump. The national environment could end up boosting Nelson, as could the coattails of gubernatorial standard-bearer Andrew Gillum. Scott has received plenty of earned media from this year’s hurricanes, but he and his allies have spent big in this expensive state and haven’t been able to put away the race.

Race Rating: Tilts Democratic

6. Jon Tester, D-Mont. 

Trump’s repeated visits to Big Sky Country — a state he won by 21 points — have helped nationalize this race, which is a good thing for the GOP nominee, state Auditor Matt Rosendale. Tester continues to lean into his brand (have you heard, he has seven fingers?) while going after Rosendale on health care, public lands and his Maryland roots. Tester has never won a Senate race with more than 50 percent. The Libertarian Party candidate appeared to throw his support to Rosendale last week, but it’s not clear if this shifts the race further away from the two-term senator. Tester remains where he was last month.

Race Rating: Tilts Democratic

7. Joe Manchin III, D-W.Va.

Manchin’s personal brand in West Virginia continues to protect him, with Republicans largely conceding he’s out of reach. The former governor’s current ranking is several spots lower than where he was when the cycle began. Manchin will always be at risk in a state Trump carried by 42 points, but GOP state Attorney General Patrick Morrisey hasn’t been able to effectively go after him, in part because of his own ties to Washington and the pharmaceutical industry. Manchin, meanwhile, has zeroed in on Morrisey’s support for a lawsuit against the 2010 health care law.

Race Rating: Tilts Democratic

8. Ted Cruz, R-Texas

Cruz still looks likely to win re-election, but with Baldwin falling off the list, he moves up to No. 8. At this point, polling shows a closer race in Texas than other Trump states such as Wisconsin, Ohio and Pennsylvania, where Democrats are also defending seats. Cruz’s well-funded Democratic opponent, Rep. Beto O’Rourkeshattered a fundraising record by raking in $38 million in the third quarter that ended Sept. 30. While O’Rourke is running closer to Cruz than expected and can compete on TV, Cruz has been holding steady at around 50 percent in recent polls.

Race Rating: Likely Republican.

9. Robert Menendez, D-N.J. 

Since Menendez’s first appearance on this list last month (at No. 10), national Democratic groups have poured millions more into New Jersey. The two-term senator is up against Republican Bob Hugin, who’s put nearly $30 million of his own money into the race. But Menendez still leads in every poll from this blue state. Even if voters are turned off by his ethical quandaries, they’re not likely to ditch him for a retired pharmaceutical executive who’s run a largely negative campaign.

Race Rating: Likely Democratic

10. Tina Smith, D-Minn.

The appointed Minnesota senator finds herself on this list for the first time, largely because a handful of Democrats facing re-election in Trump states have fallen off. Smith is running in the one Upper Midwest state that Trump did not carry in 2016, and she continues to lead GOP state Sen. Karin Housley — although sometimes by single digits — in public polling of the special election. National Democrats made a last-minute investment here last week, but that’s likely an insurance policy since Smith got a late start and wasn’t very well-known from her previous role as lieutenant governor.

Race Rating: Likely Democratic

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