How bad can it get for the GOP?

That's the question party strategists are asking themselves this week after the revelation of a video in which Donald Trump bragged about sexually assaulting women. Already, former Trump supporters like Sens. Kelly Ayotte of New Hampshire and Rob Portman of Ohio and Rep. Joe Heck of Nevada have decided to no longer back their own party's presidential nominee. Other Republicans may not be far behind.The truth is we won't know until the end of the week, when post-debate polls come in, what the full extent of the damage is (if there's much damage at all).But we do have a strong sense now, with less than a month before Election Day, which Senate challengers are running strong races — and which ones aren't. Even amid a tumultuous political climate, the individual candidates can matter a great deal.A reminder: We did not rank the challengers in order of which seats are most likely to switch party control. This is an independent assessment of the nonincumbent candidates, regardless of whether we expect them to win. Factors like fundraising, biography, and presence on the campaign trail are part of the analysis.

The list is also mostly populated by Democrats, because so many Republican incumbents are running.


1. Democratic Missouri Secretary of State Jason Kander, running against Republican Sen. Roy Blunt. (Previous ranking: No. 4)Democrats once considered Kander a good candidate who probably couldn't come out on top in red-state Missouri. Now, they believe he's their best candidate and are counting on him to win in November.Operatives from both parties say the young secretary of state likely holds a small lead over the longtime politician Blunt, a remarkable development for a race that most analysts considered a second-tier contest when the summer began. And it's mostly thanks to the strength of Kander, the rare post-Obama Democrat whose military background and familiarity with guns has appeal to culturally conservative voters. (His campaign ran what many consider the best TV ad of the election cycle that featured him assembling an AR-15 blindfolded.)Even Republicans admit it's hard to build a strong case against him, pointing to ads that do little more than call him an ally of Hillary Clinton and Barack Obama. That kind of generic argument might not go far enough with voters.


2. Republican Rep. Joe Heck of Nevada, running against Democratic nominee Catherine Cortez Masto. (Previous ranking: No. 3)Heck _ who just about everyone acknowledges holds a small lead in his Senate race  — has benefited from Trump's unexpected strength in Nevada. The GOP presidential nominee has been running about even with Clinton there, at least before the video, a far stronger showing for him than in other battlegrounds.Yet the three-term House member from a swing district is still over-performing the party's top-of-the-ticket leader, and Republicans believe he has a real shot at victory even if Democrats (as expected) make up ground in the race's final weeks.One telling indicator of the race: Democrats are working overtime to link Trump to Heck in TV ads (something they hadn't done elsewhere before last Friday's revelations), a sign that voters thus far, including Latino voters, are making a distinction between the two men. In the end, that might be the only way a candidate like Heck can win a state like Nevada that has leaned blue in recent presidential races.


3. Democratic former Sen. Russ Feingold of Wisconsin, running against Republican Sen. Ron Johnson. (Previous ranking: No. 5)It's possible Feingold hasn't received enough credit as a candidate. He entered the Wisconsin Senate race, immediately grabbed the lead against an incumbent, and has yet to relinquish it. Polls suggest he still holds a comfortable advantage in a race Democrats believe they have already won.Democrats have always believed Feingold would make for a strong candidate, but when he declared his candidacy last year, they still held lingering concerns that the ex-lawmaker might run the same kind of sub-par campaign that plagued his 2010 race. Those fears have proved unfounded.


4. Democratic former Sen. Evan Bayh of Indiana, running against Rep. Todd Young. (previous ranking: No. 1)Bayh slips down these rankings, though last month's assessment remains true: He's the only Democratic candidate who could have even made this open-seat, red-state race competitive.Still, Democrats probably wish the hits against him weren't quite so tough or numerous. The latest, a report in USA Today that he spent more than $200,000 in taxpayer money chartering flights as a senator, helps Republicans argue that he is more interested using his office to help himself rather than the public.Bayh, who served two terms each as Indiana senator and governor, remains relatively popular _ how else could he hope to win a conservative state? But polls that show the race in a dead heat probably aren't off by much despite the huge edge he held just a few months ago.


5. Democratic Gov. Maggie Hassan of New Hampshire, running against Republican Sen. Kelly Ayotte. (Previous ranking: No. 2)Hassan's favorable numbers are strong. Her fundraising, at least for a small-state race, is prodigious. Democrats continue to consider her one of their best recruits of the cycle.But the governor might yet prove unlucky in opponents. These rankings don't include incumbents, but it's hard to ignore how successfully Sen. Kelly Ayotte has over-performed Trump in the Granite State (her role-model gaffe in last week's debate notwithstanding.)If Hassan can't win this race, it's unlikely any Democratic candidate could have.


6. Democratic Rep. Tammy Duckworth of Illinois, running against Republican Sen. Mark S. Kirk. (Previous ranking: No. 8)Duckworth has proved up to the task of holding a comfortable lead against Kirk, who, despite his campaign's evident struggles, is the kind of socially moderate, anti-Trump Republican who could actually win in blue-state Illinois.She's so confident in her race, in fact, that the double-amputee was scheduled to finish a marathon in Chicago this past weekend. It's about the most notable thing that's happened in her otherwise sleepy campaign.


7. Republican Rep. Todd Young of Indiana, running against Bayh. (Previous ranking: No. 6)Young is the kind of fresh-faced, former Marine who gives Republicans a winning contrast with Bayh. But he's playing a decidedly supporting role in a race that has otherwise become a referendum on the longtime Indiana politician.Young's big upcoming test: Can the 44-year-old excel in the upcoming debates?


8. Democratic former state Rep. Deborah Ross of North Carolina, running against Republican Sen. Richard M. Burr. (Previous ranking: No. 7)Ross still deserves credit for making a race that, six months ago, few thought would be competitive in a contest Democrats now consider a top pickup opportunity.But whether this former state lawmaker can seal the deal against Burr will depend largely on how voters feel about her history as head of the state's American Civil Liberties Union. Republicans, last month, began an ad campaign noting her previous criticism of a sex-offender registry list. The effects of that effort, they say, won't be evident in the polls until the coming weeks.These kinds of attacks are why Democrats were once nervous about Ross as the nominee — and why they might be now, again.


9. Democratic Rep. Ann Kirkpatrick of Arizona, running against Republican Sen. John McCain. (Previous ranking: 9)It's not easy to rank Kirkpatrick. Democrats have largely given up hope that the battle-tested congresswoman can defeat McCain, though that's mostly a comment on the incumbent Republican's own popularity.Still, she hasn't done much to change the trajectory of her race despite raising a decent chunk of change. Time is running out for her to change that.


10. Democratic former Nevada Attorney General Catherine Cortez Masto, running against Heck (Previous ranking: No. 11)Cortez Masto isn't doing all that bad, considering Trump's strength in her home state. But if she wins, she'll need to ride Clinton's coattails to do so.Like a lot of candidates on this list, her performance in the upcoming debate will be heavily scrutinized.


11. Democratic former White House official Katie McGinty of Pennsylvania, running against Republican Sen. Patrick J. Toomey (Previous ranking: No 10)McGinty is gaffe-prone and campaigns without charisma. But she is running hard, raising plenty of money and successfully positioning herself to carry a state Clinton could win big.Some Democrats wonder whether Joe Sestak, the former congressman whom McGinty defeated in the primary, would be doing better. That's hard to say, but national Democrats who forcefully backed McGinty's candidacy aren't having any regrets.


12. Democratic Rep. Patrick Murphy of Florida, running against Republican Sen. Marco Rubio. (Previous ranking: No. 12)In the end, national Democrats abandoned Florida because of its immense size, expensive media markets, and Rubio's evident popularity. But it's just as fair to conclude that persistent, damaging questions about Murphy's business background made him not quite the candidate Democrats were hoping for when he entered the race last year.


13. Democratic former Gov. Ted Strickland of Ohio, running against Republican Sen. Rob Portman. (Previous ranking No. 14) Strickland moves up this list only because Iowa Democratic nominee for Senate Patty Judge fell off it completely. His stumbling performances on the campaign trail, target-rich record, and inability to raise much money  — even when things were going well — make him the worst Democratic candidate of the cycle, at least in states once viewed as winnable.