Top Republican and Democratic senators pledged Tuesday to deepen their investigation of Russian involvement in the 2016 presidential election in the wake of Michael Flynn’s resignation as President Trump’s national security adviser, opening a new and potentially uncomfortable chapter in the uneasy relationship between Trump and Capitol Hill.

Senate Majority Leader Mitch McConnell (R-Ky.) said such an investigation is “highly likely,” and the top two members of the Senate Intelligence Committee, Sen. Richard Burr (R-N.C.) and Sen. Mark R. Warner (D-Va.), stood side by side Tuesday to announce that the committee’s ongoing probe must include an examination of any contacts between Trump campaign officials and the Russian government.

Flynn resigned late Monday after revelations of potentially illegal contacts with Russia last year and misleading statements about the communication to senior Trump administration officials, including Vice President Pence.

“We are aggressively going to continue the oversight responsibilities of the committee as it relates to not only the Russian involvement in the 2016 election, but again any contacts by any campaign individuals that might have happened with Russian government officials,” said Burr, the chairman of the intelligence panel.

Added Warner, the vice chairman, “The press reports are troubling, and the sooner we can get to the veracity of those press reports or not, then we’ll take the next appropriate step.”

(Deirdra O'Regan/The Washington Post)

The consensus among lawmakers came at a tense moment, when congressional Republicans were already finding it difficult to defend Trump as the tempestuous start to his term has stoked frustration, fatigue and fear on Capitol Hill.

Many congressional Republicans have endured Trump’s unpredictability — including his criticism of the federal judiciary, and an immigration order that caught them by surprise and drew intense national blowback and a legal rebuke — because they think he holds the key to passing laws they have talked about for years.

Rep. Mark Meadows (R-N.C.), chairman of the Freedom Caucus, a conservative group of House members, put it this way: “I would rather accomplish something with distractions than not accomplish anything with smooth sailing.”

Burr and Warner’s agreement is also striking given the partisan feuding that has characterized investigations into Russia and the election — and relationships on Capitol Hill generally. The two senators were initially at odds over whether the committee’s probe should include potential ties between Trump campaign officials and the Russian government, with Burr suggesting that it was outside the panel’s purview.

On Tuesday, Burr defended the committee’s right to look at those potential contacts, including any that may have occurred before Trump’s inauguration. And he has the support of Senate GOP leadership; in addition to McConnell, Sen. John Cornyn (Tex.), the majority whip, and Sen. Roy Blunt (Mo.), the GOP conference vice chairman, also called for investigations into Flynn’s actions.

Their pronouncements contrasted sharply with remarks by Republicans in the House, who applauded Flynn’s resignation but for the most part stopped short of calling for further investigation.

“I’ll leave it up to the administration to describe the circumstances surrounding what brought [Flynn] to this point,” House Speaker Paul D. Ryan (R-Wis.) told reporters.

Michael Flynn resigned Monday from his post as President Trump’s national security adviser. (Evan Vucci/AP)

Some took aim elsewhere. House Intelligence Committee Chairman Devin Nunes (R-Calif.) said the most significant question posed by Flynn’s resignation is why intelligence officials eavesdropped on his calls with the Russian ambassador and later leaked information on those calls to the news media.

“I expect for the FBI to tell me what is going on, and they better have a good answer,” Nunes said. “The big problem I see here is that you have an American citizen who had his phone calls recorded.”

Democrats cautiously applauded plans to expand the Senate investigation, even though several of them had called for an independent probe run by a special prosecutor. McConnell and Republicans will certainly have more control over an in-house investigation, but even Warner said he favors that approach.

“Not only do we have oversight over intelligence and counterintelligence, but it works in a bipartisan basis,” Warner told reporters.

Many Democrats think the slow, painstaking but largely public process of an independent commission, such as the 9/11 Commission, is preferable to leaving the investigation in the hands of committees that work in secret, giving leaders more latitude to pull political strings.

Senate Minority Leader Charles E. Schumer (D-N.Y.) called for “unbiased” law enforcement officials to lead a federal investigation, adding that Attorney General Jeff Sessions cannot be involved in any probe given his close political connections to the White House and Trump’s presidential campaign.

In the past, such secrecy has allowed certain high-profile intelligence committee proceedings to fall victim to partisan infighting; that happened in the Senate in 2014, when then-chairman Dianne Feinstein (D-Calif.) tried but failed to release the full “torture report” on CIA interrogation methods.

In the House, such divisions are already on display, as the House Intelligence Committee’s ranking Democrat, Rep. Adam B. Schiff (Calif.), has angled to establish at least a joint congressional inquiry to look into the allegations against Flynn.

Nunes, the committee chairman, has almost unfettered control over the process, with the unilateral power to issue subpoenas — as would be necessary to compel Flynn to testify. In the Senate Intelligence Committee, members vote on whether to issue subpoenas.

When asked if he would call Flynn to testify, Burr said: “We won’t exclude that.”

Blunt told KTRS radio in St. Louis that the committee should talk to Flynn “very soon.”

“I think we should look into it exhaustively so that at the end of this process, nobody wonders whether there was a stone left unturned, and shouldn’t reach conclusions before you have the information that you need to have to make those conclusions,” Blunt said in the interview.

The House and Senate intelligence committees had already launched broad investigations into Russian involvement in the U.S. election, including the possibility of ties between Moscow and any candidates and their campaigns.

But the news about Flynn’s contact with Russians prompted an ad hoc gathering of the Senate Intelligence Committee on the Senate floor Tuesday. At least seven senators participated in the long, animated discussion. One participant, who spoke on the condition of anonymity to discuss the private conversation, said senators encouraged Burr to be more aggressive with the probe.

[As Trump stumbles, Hill Republicans find it harder to defend him]

Burr was told, according to the participant, that if the intelligence panel did not step up, other committees would fill the void.

Burr has been less publicly aggressive than some other Republicans, particularly Sens. John McCain (Ariz.) and Lindsey O. Graham (S.C.), who are launching their own inquiries on the Armed Services Committee. They have pushed, unsuccessfully so far, for the creation of a special committee to handle an investigation into Russia and last year’s elections.

Although it remains unclear who was being targeted during Flynn’s conversations with Russian Ambassador Sergey Kislyak, the Russians’ calls are routinely monitored.

Flynn’s critical conversations with Kislyak took place in December — before executive privilege could apply, Democrats point out, but well after the elections were over.

In the House, Schiff said he has not yet discussed with Nunes whether the scope of the committee’s probe could be expanded to cover the transition period, though he noted that “it ought to be a natural extension of what we do.”

Over in the Senate, a similar tweak to plans would appear to be necessary to allow the Intelligence Committee to examine ­Flynn’s contacts with Russian authorities, as many leading Republicans believe is necessary.

Sen. Bob Corker (R-Tenn.) suggested that it “would certainly be useful” to publicly release the transcripts of Flynn’s conversations with Kislyak.

Schiff pointed out during a Democratic news conference Tuesday that Intelligence Committee officials have not yet received transcripts or tape recordings of those conversations.

“Those, I think, are things I think we ought to get as part of the Gang of Eight,” Schiff said.

Added House Minority Leader Nancy Pelosi (D-Calif.): “Before they destroy them.”

Ed O’Keefe, Mike DeBonis, Karen DeYoung, Greg Miller and Philip Rucker contributed to this report.

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