Republicans have expressed fears that US President Donald Trump may lose next month's election to Democrat Joe Biden.
Polls as of October 9 show Biden is on 52.1 points and Trump is on 42, according to poll aggregate FiveThirtyEight.
Republican Senator Ted Cruz says he's "worried" about how volatile voters could be.
"If on Election Day people are angry and they've given up hope and are depressed - which is what [US Speaker Nancy] Pelosi and [Senate minority leader Chuck] Schumer want them to be - I think it could be a terrible election," he told CNBC on Friday.
"I think we could lose the White House and both houses of Congress, that it could be a bloodbath of Watergate proportions."
Senator Thom Tillis, who is seeking re-election in North Carolina and is also one of several Trump associates who tested positive for COVID-19, raised the idea of a Biden win during a debate earlier in October.
"The best check on a Biden presidency is for Republicans to have a majority in the Senate," he said.
If the Democrats continue to hold the House of Representatives and win back the Senate and the White House, the party would have complete control of the federal government.
"Checks and balances does resonate with North Carolina voters," Tillis added.
Senate majority leader and Republican Mitch McConnell said he hasn't been to the White House since early August due to Trump's handling of COVID-19 protocols.
"My impression was that their approach to how to handle this is different from mine and what I suggested that we do in the Senate, which is wear a mask and practice social distancing," he said on Thursday.
"If any of you have been around me since May the 1st, I've said 'wear your mask, practice social distancing, it's the only way we know of to prevent the spread until we get a vaccine'."
Trump has downplayed the pandemic, previously saying COVID-19 "affects virtually nobody" and viewed the US' number of cases as a "badge of honour" since he believed it reflected the country's testing capacity.
Other Republicans have also distanced themselves from Trump, with Senator Martha McSally refusing to say during a debate whether she supported the President, and Senator John Cornyn slamming Trump for the "confusion" he created around COVID-19.
