Republicans running for office are facing the same question they have been asked in elections since 2016: how aligned are they with President Donald Trump?

Conservatives who have bucked the president in the past have generally not fared well with voters.

The president has seen low approval ratings in recent months, with polls suggesting voters are largely concerned with the cost of living and high fuel prices.

While some Republican candidates have remained in lockstep with Trump, a Reuters analysis indicated, external that two-thirds of candidates in competitive US House and Senate races have broken with the president in some way this election cycle.

Susan Collins, a Maine Republican running for her sixth term in the Senate who has repeatedly broken with Trump, is again putting clear distance between herself and the president.

"I voted with President Biden 91% of the time," Collins said during a debate last week.

"The fact is, this year alone, this Congress alone, I voted against President Trump 137 times," she said.

Collins is fighting a tighter Senate race than she expected against Democrat Troy Jackson, the former president of the Maine Senate. A New York Times/Siena University poll from mid-September suggests Collins could be ahead in that race by 3%, while others indicate Jackson is in the lead.

There are 35 Senate seats up for grabs this November, but in 21 there are no debates scheduled among the main candidates, an ABC News analysis found.

One race's lack of debates has surprised many observers: the Texas contest between James Talarico, a Democratic state representative, and Ken Paxton, a Republican and former state attorney general.

Polls in the typically Republican state suggest that Talarico could be in reach of a surprise win. Should he succeed, he could help give Democrats control of the US Senate by flipping one of the four seats they need to create a majority.

Talarico has accepted four debate invitations from different news networks. Paxton, meanwhile, has not accepted any of those invitations.

In July, Paxton's campaign spokesperson told media outlets that he would debate Talarico. But since then, the campaign, and Paxton, have said little on the matter. Trump, who backed Paxton in the Republican primaries, has even urged the candidates to debate.

"One thing about not showing up is you lose the opportunity to make the case for yourself, and instead, what you do is you give your opponent the ability and the opportunity to make your case as negative as possible," Peter Trumbore, a political science professor at Oakland University, told the BBC's US partner CBS News last month.