Donald Trump is forcing congressional Republicans into survival mode

Donald Trump's slip in the polls this past week has Republicans reportedly worried that their choice at the top of the ticket could drag down Congressional races they need to win in order to maintain control of the House and Senate.

While some notable Republicans have denounced or distanced themselves from Trump, many running for reelection have stuck by their party's choice for the Oval Office.

But a number of anonymous sources told The New York Times that could soon change - especially if the Manhattan billionaire performs poorly at the second presidential debate on Sunday.

Pundits, focus groups, and then polls concluded that Trump's Democratic opponent, Hillary Clinton, won the first debate. The week following it was filled with disagreements between Trump and former Miss Universe Alicia Machado, whom he called fat and encouraged people to "check out [her] sex tape and past."

While the Republicans' control over the 435-member House of Representatives isn't likely to change, Democrats could reclaim the Senate this election. Of the 34 seats that are up for grabs, Republicans held 24, and Democrats held 10.

But most of those GOP seats were Tea Party members who swept into office in 2010 after the Democratic-controlled Congress passed the Affordable Care Act, Ballotpedia explains. If Hillary Clinton wins the presidency and her running mate Tim Kaine becomes the tie-breaking 101st vote in the Senate, Democrats would only need to win 16 of the open seats to have a majority.

Democrats are projected to take back a number of those seats, and the likelihood has grown even more favorable in the last week. Nate Silver's election forecast at FiveThirtyEight now has Democrats with a 61.5% chance of winning back the Senate.

The next presidential debates could make it even more clear whether congressional Republicans seeking reelection will have to run from their nominee to save themselves. The second debate between Donald Trump and Hillary Clinton happens at 9 p.m. ET, October 9.