A bipartisan group of senators say they want to investigate whether Russia interfered with the 2016 U.S. election, amongst claims that Donald Trump's rhetoric on Russia and Vladimir Putin is too soft. (Peter Stevenson/The Washington Post)

Congressional leaders are vowing to vigorously probe allegations that Russia interfered in the elections to benefit President-elect Donald Trump, but they are already arguing over who should do so and how any examination should be conducted.

Senior Republicans want to channel any investigation through the House and Senate intelligence committees, over which they have greater control. But some Democrats, fearing that the results of such an investigation would never be released to the public, are pushing the formation of an independent body of outsiders modeled on the Sept. 11 commission.

Still other Republicans would like to see a bipartisan investigation in Congress — or better yet, form entirely new congressional committees and subcommittees to dig into the matter. A different group of Democrats would like to see a very unusual bicameral probe into whether Russia allegedly hacked the Democratic National Committee emails and leaked them to WikiLeaks in a concerted effort to damage Hillary Clinton.

The cacophony of competing voices on Capitol Hill could hamstring the rare, near-universal commitment to dig into allegations Russia interfered with the 2016 election. It may also allow Trump to discredit lawmakers’ efforts as overly partisan — the president-elect has called charges that Russia interfered in the election to benefit his candidacy “ridiculous.

In public statements, Senate Majority Leader Mitch McConnell (R-Ky.) and House Speaker Paul D. Ryan (R-Wis.) have both focused on channeling any Russia investigation through their intelligence committees.

Senate Majority Leader Mitch McConnell of Ky. speaks on Capitol Hill in Washington on Dec. 8. (Cliff Owen/AP)

McConnell on Monday said the Senate Intelligence Committee — of which he is a symbolic member as the chamber’s GOP leader — is “more than capable of conducting a complete review of the matter.” Ryan agreed, saying that a special panel is unnecessary because the House Intelligence Committee is “working diligently on the cyberthreats posed by foreign governments and terrorist organizations.”

But if history is any guide, those investigations could be highly classified and damaged by partisan infighting. Their findings may be subject to presidential review and closely held by top lawmakers, the intelligence community and senior aides in the Trump White House.

“There certainly is a danger in this being swept under the rug,” said Oregon Sen. Ron Wyden (D), an Intelligence Committee member. “There must be urgency and transparency in getting facts out into the open, whether they’re being investigated by the intelligence committees, other standing congressional committees, a joint committee or an independent commission.”

“One of the goals of this investigation should be to release as much information as possible, while protecting sources and methods,” said Virginia Sen. Mark R. Warner, who will be the ranking Democrat on Intelligence starting in January.

The closest parallel may well be the so-called “torture report,” produced in 2014 by the Senate Intelligence Committee documenting CIA treatment of suspected terrorist detainees in the wake of the Sept. 11, 2001, attacks. Despite then-chairwoman Dianne Feinstein’s (D-Calif.) intense desire to see the full 7,000-page report released, all but the 528-page executive summary has remained private.

That panel devolved into near chaos when the torture report was released without the support of Republicans, including the incoming chairman of the Intelligence Committee, Sen. Richard Burr (R-N.C.). When he became chairman, Burr demanded the return of all copies of the report, apparently concerned that it could be obtained through the Freedom of Information Act.

President Obama this week made moves to preserve the report when he leaves office without ensuring that it immediately becomes available to the public.

Obama has also taken steps to collect information about the CIA allegations before he leaves office on Jan. 20, ordering a “full review” of the charges be delivered to him before he leaves office. Separately, a group of senior Democratic senators is pushing Obama to declassify information about Russia’s alleged election-related hacking operations before Trump is inaugurated.

Russian President Vladimir Putin’s spokesman on Tuesday issued a blunt denial of U.S. allegations that the Kremlin intervened to help Trump win the presidency, and expressed hope that Moscow will be able to “reset” its relationship with the new administration.

In an interview with RT television, Dmitry Peskov dismissed the findings by the CIA that the Russian government aided Trump — and other assertions that it was interfering in upcoming German elections — as “absolute nonsense.”

The battle over how to investigate Russian influence is likely to bleed over into the confirmation hearings of ExxonMobil chief executive Rex Tillerson, who was nominated on Tuesday by Trump to be his secretary of state. Several Republicans in the Senate, which must vote to confirm Tillerson, expressed concern over ties Tillerson has to Putin, who decorated him with the Kremlin’s Order of Friendship in 2013.

“While Rex Tillerson is a respected businessman, I have serious concerns about his nomination,” Sen. Marco Rubio (R-Fla.), a member of the Senate Foreign Relations Committee, which will hold confirmation hearings, said in a statement. “The next secretary of state must be someone who views the world with moral clarity, is free of potential conflicts of interest, has a clear sense of America’s interests, and will be a forceful advocate for America’s foreign policy goals to the president, within the administration, and on the world stage.”

McConnell, however, backed Tillerson, saying, “I look forward to supporting” his nomination.

The House and Senate intelligence panels have already had briefings from various officials pertaining to allegations that Russia interfered in the elections. But in the House, the committee's chairman, Devin Nunes (R-Calif.), has also criticized Director of National Intelligence James R. Clapper Jr. for presenting the committee with a different take on Russia’s hacking activities than the CIA assessment that the Kremlin interfered to help Trump win.

The committee “has an urgent need to accurately understand the current IC assessment of alleged Russian cyberactivities relating to the election, and any disagreements among IC components,” Nunes wrote in a letter to Clapper on Monday.

In a separate statement Monday, Nunes also said that he “do[es] not see any benefit in opening further investigations.”

But so far, those committees haven’t made any of their current information public, and they may not do so if they broaden their reach.

To avoid such a situation, Senate Democrats — including Feinstein — have called for an independent commission of experts, appointed by congressional leaders, to investigate the allegations. House Minority Leader Nancy Pelosi (D-Calif.) also supports that approach, in which both sides would have subpoena power.

Such a committee would be structured like the Sept. 11 commission, with both parties’ leaders appointing one to two non-lawmakers to sit on it. The president would not be allowed to appoint panel members, a courtesy often extended during the creation of other commissions, as Democrats believe Trump would have a conflict of interest because of the nature of the allegations. Democrats want a report made public 18 months after such a panel begins its work.

McConnell, Ryan and other committee leaders — including Trump’s most vocal critics on the Hill — have been dodging direct questions about whether they believe the CIA’s assessment that Putin, whom Trump frequently praised during the campaign, was behind the hacks the CIA thinks were intended to help Trump prevail.

Senate Armed Services Committee Chairman John McCain (R-Ariz.), who has said “there’s very little doubt” Russia intervened in the elections and has derided Trump for casting doubt on that conclusion, suggested that in this one instance, maybe the CIA is wrong.

“The CIA has not always been exactly right, to say the least,” he said.

In the wake of the CIA allegations, however, McCain and Sen. Lindsey O. Graham (R-S.C.) joined calls from incoming Senate Democratic leader Charles E. Schumer (N.Y.) to initiate a bipartisan probe.

For McCain, the election is one part of a larger examination that must focus on national security risks posed by cyberthreats, particularly related to the military. Officials already suspect that Russia may have been behind a major email breach at the Pentagon last year.

Sen. Bob Corker (R-Tenn.), who chairs the Foreign Relations Committee, has also pledged to dig into the allegations of Russian hacking next year. And Sen. Lindsey O. Graham (R-S.C.), who chairs subcommittees on the Judiciary and Appropriations committees, has also committed to investigating Russia’s alleged intervention in the elections, as well as other nefarious activities across the globe, including in the conflicts in Syria and Ukraine.

David Filipov in Moscow and Kelsey Snell in Washington contributed to this report.