WASHINGTON — President Trump faces a deadline today to produce evidence for lawmakers investigating his Twitter claim that former President Barack Obama illegally wiretapped his Trump Tower offices before the election.

But it’s congressional Republicans, including those who avidly support Trump and his agenda, who could face their own political heat in the 2018 elections based on how they handle the claims, which have been dismissed by Obama and intelligence officials.

“The basic bottom line is that there are 23 congressional districts where there are Republican incumbents but Hillary Clinton won those districts,” said Democratic strategist Brad Bannon. “Those are seats that are most likely to go to Democrats.”

House Intelligence Committee chairman and former Trump campaign surrogate Rep. Devin Nunes, (R-Calif.) and ranking Democrat Rep. Adam Schiff (D-Calif.) gave the Trump administration until today to provide proof of the president’s claim, which is part the committee’s probe of election tampering by Russian officials.

Other Republicans are also calling for quick action from Trump, who has declined to produce evidence of the claim he made last week, instead calling on Congress to investigate.

“President Trump has to provide the American people — not just the Intelligence Committee, but the American people — with evidence that his predecessor, a former president of the United States, was guilty of breaking the law,” said Sen. John McCain (R-Ariz.) in a CNN interview yesterday.

Noting that former director of national intelligence James Clapper testified that there was no truth to Trump’s allegation, McCain added, “The president has one of two choices: either retract or to provide the information that the American people deserve.”

While congressional Republicans have largely backed Trump since the inauguration, they have largely pushed for a quick resolution to his wiretapping claim and tried to focus on other areas. Yesterday House Speaker Paul Ryan said in an interview on CBS’ “Face the Nation” that he’d seen no evidence wiretapping took place.

“That’s outside of my control, what is tweeted or what isn’t tweeted,” Ryan said. “We’re focused on health care.”

But the backlash is less likely to harm the president, even if his claim that Obama committed a crime proves false, experts said.

“Like everything else, it will blow over,” said Republican strategist John Feehery.

“On the other hand, if Trump is proven right, it will be the biggest scandal since Watergate — and he will be the victor,” said GOP strategist Ford O’Connell.