Comey bombshell reverberates through Senate races

FBI Director James Comey's October bombshell is already reverberating further down the ballot.

The surprise disclosure Friday that his agency is probing emails related to Democratic candidate Hillary Clinton has delivered a major blow to both her campaign and her party's hopes of retaking control of the Senate.

It's also created a headwind for down-ballot Democrats hoping to capture seats from the GOP in close races by winning over the remaining undecided vote. Many of the Republicans in those tight Senate races had sought to distance themselves from setbacks in GOP nominee Donald Trump's campaign. Now, the Comey disclosure has put Senate Democrats on the defensive.

The stakes, like much of the rest of this election, are high.

If Clinton wins, Democratic control of the Senate would ease confirmation of her appointments, including a new Supreme Court justice. A Republican-controlled Congress could effectively thwart much of any Clinton presidential agenda.

If Donald Trump is the winner, a Democratic-controlled Senate could provide a check on his legislative agenda, which would prove harder to block if the GOP controls both chambers.

While a number of House races remain close, the Democrats have a much slimmer chance of capturing the 218 seats needed to wrest control from Republicans.

To take control to the Senate, Democrats need a net gain of four seats, for a total of 50, if Clinton wins. (With 50 seats, her running mate, Tim Kaine could cast a tie-breaking vote.) If GOP rival Trump becomes president, the Democrats need a net gain of five seats, giving them a 51-49 majority.

So here's the math. Of the 34 Senate seats up for re-election this year, 10 are currently held by Democrats and 24 held by Republicans. Of those, nine are considered safely or likely to remain in Democrats hands and 17 are expected to remain in GOP control.

That leaves the eight toss-up states, seven of which are currently represented by Republicans: Illinois, Indiana, Missouri, New Hampshire, North Carolina, Pennsylvania and Wisconsin. In Nevada, Democrat Harry Reid is retiring, Republicans have a shot at picking up another seat.

Democrats appear to be on track to flip at least two of those seats. In Wisconsin, former Democratic Sen. Russ Feingold holds a nearly 7 point polling lead against incumbent Republican Sen. Ron Johnson, according to the average poll results tracked by Real Clear Politics. In Illinois, incumbent Republican Sen. Mark Kirk has trailed Democratic challenger Tammy Duckworth in the polls, which have more recently widened in her favor.

If those trends hold, Democrats would need another two seats if Clinton wins, or three seats if Trump becomes president.

Here's how the remaining toss-up races break down, state by state:

Indiana

Though Indiana has typically been a reliably red state, the retirement of Republican Sen. Dan Coats has given an opening to Democrat Evan Bayh, a former governor and senator who retired in 2011. While the race is expected to be close, Bayh maintains a nearly 4 point lead in the polls with less than three weeks left in the campaign.

Missouri

GOP Sen. Roy Blunt held a comfortable lead through the summer, but his race against Democrat Jason Kander, Missouri's secretary of state, has tightened considerably, with just a single polling point — less than the margin of error — separating the two with a week remaining. The final count is expected to be close.

Nevada

GOP Rep. Joe Heck is hoping to flip this Senate seat from blue to red, after the retirement of Senate Minority Leader Harry Reid. But Reid's handpicked replacement, Catherine Cortez Masto, has closed the gap to a virtual dead heat. Heck has tried to distance himself from Trump, calling on him to quit the presidential race after the release of the "Access Hollywood" tape capturing his demeaning comments about women.

New Hampshire

Clinton's lead in the Granite State against Trump may also help Democratic Gov. Maggie Hassan in her bid to unseat incumbent Republican Sen. Kelly Ayotte, who has struggled to distance herself from Trump after earlier citing him as a role model for children. Ayotte is holding onto a slim lead in the polls.

North Carolina

Once considered a safe Republican seat, incumbent Sen. Richard Burr is in a tough fight against Democrat Deborah Ross, a former state legislator, who briefly led Burr in the polls earlier this month. Burr's campaign has also benefited from Clinton's aggressive campaigning in the Tar Heel State, where Burr leads by a single polling point. As of Monday, Clinton maintained 3 point lead against Trump in the state.

Pennsylvania

Democrats are also hoping to flip a Republican seat in Pennsylvania, where incumbent GOP Sen. Pat Toomey is trailing Democratic challenger Katie McGinty by 2 points. Pennsylvania has a split congressional delegation but has voted for Democrats at the top of the ticket in the last six presidential elections.