Though they still face an uphill battle to win control of the House, Senate Democrats in tight races maintain optimism as GOP presidential candidate Donald Trump's support continues to wane and down-ballot Republicans scramble to distance themselves from his campaign.

In the latest polls, Trump continues to lose ground to Democratic presidential rival Hillary Clinton, following a controversial attack on the U.S. election process itself in Wednesday's third and final debate. Trump claimed the upcoming presidential vote is has been "rigged" against him, and has pointedly declined to say whether he would accept the results if he loses.

On Wednesday, Trump pledged to keep the country "in suspense" in an unprecedented campaign challenge to the legitimacy of the U.S. electoral system.



"I will look at it at the time. I'm not looking at anything now," he said when asked directly if he would accept the results on Election Day, which is less than three weeks away.

The backlash to Trump's remarks only added to widespread fears among Republicans that disillusioned party members could abandon GOP House and Senate candidates further down the ballot. Democrats have grown increasingly confident that they have a shot at regaining control of one or both chambers of Congress.