Sen. John McCain (R-Ariz.) speaks with U.S. service members on Jan. 2 on a visit to the NATO-Georgia Joint Training and Evaluation Center in Krtsanisi, outside Tbilisi, Georgia. (Zurab Kurtsikidze/European Pressphoto Agency)

President-elect Donald Trump’s broadside against the intelligence community is dividing Capitol Hill Republicans, with some ready to pounce on Trump’s skepticism that Russia interfered with the U.S. elections and others urging a more cautious approach.

The resulting schism could widen as Congress begins probing the CIA’s charges that Russia intervened in the November elections in an attempt to help Trump, potentially becoming one of the first significant intraparty breaches of the Trump presidency.

U.S. critics of Russian President Vladi­mir Putin, such as Sens. John McCain (R-Ariz.) and Lindsey O. Graham (R-S.C.), want to go full-bore on holding Russia to account for its suspected election interference. But they may be slowed by GOP senators who prefer to wait to hear the intelligence community’s evidence and for Trump to be installed in the White House.

When asked whether he would be influenced by Trump’s Tuesday tweet about a supposedly delayed “Intelligence” briefing on ­“so-called” Russian hacking, McCain said flatly, “No.”

(Sarah Parnass/The Washington Post)

McCain will hold a Senate Armed Services Committee hearing Thursday on “foreign cyber threats” that is expected to center on Russia. Intelligence officials — including Director of National Intelligence James R. Clapper Jr., Defense Undersecretary for Intelligence Marcel J. Lettre II and U.S. Cyber Command and National Security Agency Director Michael S. Rogers — will testify, and some Republicans are hoping they will present evidence that Russia meddled in the elections.

“The point of this hearing is to have the intelligence community reinforce, from their point of view, that the Russians did this,” Graham said. “You seem to have two choices now — some guy living in an embassy, on the run from the law for rape, who has a history of undermining American democracy and releasing classified information to put our troops at risk, or the 17 intelligence agencies sworn to defend us. I’m going with them.”

Graham was referring to Julian Assange, the WikiLeaks founder accused of helping Russia leak emails hacked from the Democratic National Committee. He has few fans in Congress — on Wednesday, House Speaker Paul D. Ryan (R-Wis.) called Assange a “sycophant for Russia.”

Assange has denied he received leaked emails from the Russians. Trump echoed Assange in a tweet Tuesday in which he said “a 14-year-old could have hacked Podesta,” referring to Hillary Clinton’s former campaign chairman, John Podesta. Trump also tweeted support for Assange’s comment that the media is “dishonest.”

Assange’s first claim may be narrowly accurate — Russia’s intelligence services used middlemen to deliver the purloined files, said senior U.S. officials who spoke on the condition of anonymity because of the sensitivity of the information. But U.S. spy agencies are in full agreement that Russia directed the hacking and orchestrated email dumps to WikiLeaks to help Trump win — a finding at the heart of a classified assessment completed this week.

Trump’s online endorsement of Assange is his latest insult to the U.S. intelligence community and is likely to intensify the antagonism between the president-elect and U.S. spy agencies. He has repeatedly disparaged their work and skipped most of the daily briefings prepared for a future White House occupant.

CIA veterans said the level of open hostility is extraordinary. “I can’t think of any transition during my career as seemingly fraught as this one,” said John Rizzo, the CIA’s former acting general counsel.

Trump is slated to meet with U.S. spy masters this week when Clapper, CIA Director John Brennan and FBI Director James B. Comey brief him in New York on the intelligence surrounding Russia’s involvement in the election hacks. Retired Lt. Gen. Michael T. Flynn, whom Trump previously named as his national security adviser, will probably be present, adding to the tension — he was fired by Clapper as director of the Defense Intelligence Agency.

Trump has been weighing an overhaul, but not elimination, of the office of the Director of National Intelligence (DNI) for weeks, a matter that has factored into the delay in nominating someone to serve in that position, according to members of Trump’s inner circle.

Trump’s top advisers on intelligence matters are deeply skeptical of the value of the DNI position, an office that was created to spearhead post-Sept. 11 reforms of the intelligence community but has become the center of its own swelling bureaucracy.

Rep. Devin Nunes (R-Calif.), the chairman of the House Intelligence Committee and a senior member of Trump’s transition team, has voiced doubt about the value of the DNI role.

The threat to dismantle the DNI office, first reported by the Wall Street Journal, may also be designed to send a message in advance of the high-stakes intelligence briefing on Friday, reminding Clapper and others scheduled to attend that Trump holds significant power over the fates of their agencies.

Trump has been sharply critical of the CIA, particularly its conclusion that Russia waged a cyber campaign to help Trump defeat Hillary Clinton. But his pick to lead the CIA, Rep. Mike Pompeo (R-Kan.), has not indicated in recent conversations with current and former agency employees that he is planning a major shake-up, former U.S. intelligence officials said.

Rep. Adam B. Schiff (Calif.), ranking Democrat on the House Intelligence Committee, said “any move to arbitrarily slash the [DNI] office will diminish its effectiveness and reverse many of the important gains we had made since 9/11.” Moreover, Schiff said in a statement issued Wednesday, “to propose changing the CIA’s operational structure because of loose allegations of politicization — claims based on nothing more than the Agency’s willingness to contradict the President-elect’s preferred version of events — would be a mistake of the highest order.”

The Armed Services Committee hearing Thursday will give intelligence chiefs an early chance to publicly contradict Trump’s position. But some committee Republicans said it was appropriate at this point for Trump to be openly challenging the assertions of intelligence officials.

“You live by the sword, then be prepared to fight by the sword,” said Sen. Thom Tillis (R-N.C.), referring to the intelligence community. “You release information before you’re prepared to put out the facts, then be prepared for people to react to that.”

“The intelligence community some time ago back said they had compelling evidence that there was an issue,” Tillis said. “Well, maybe they should have waited and leaked that when they could produce the evidence, and then they could have eliminated this whole discourse.”

The Senate Foreign Relations Committee will also hear from State Department officials Thursday in a closed-door briefing to kick off its investigation into Russian hacking.

Clapper’s office on Thursday will brief President Obama on a promised classified report into the allegations of Russian hacking; Trump will be briefed on it Friday.

Sen. Deb Fischer (R-Neb.) suggested it was natural for Trump to be skeptical until that briefing, given he is not yet president. She also implied that some transition politics between Obama’s and Trump’s teams may be at work. “Mr. Trump hasn’t been briefed by the intelligence community is my understanding,” Fischer said. “There is a report that’s coming out, and the president has frozen all briefings. I’ve tried to have a classified briefing before the hearing, and I was told that was not possible, that it’s been frozen.”

“Hopefully, [the Obama] administration will give access to the Congress, as well,” Fischer said. “This is the first time I’ve been turned down for a classified briefing, and I’ve been on the committee four years.”

Congressional Republicans, with a few exceptions, are far more skeptical of Russia than Trump has been during and since the campaign, when he praised Putin and touted the benefits of friendlier relations. Even those willing to give Trump some room on the issue say Russia is a bad actor, citing Moscow’s annexation of Crimea, its bombing campaign in Syria and continued aggression against border states in Europe.

Republicans are staking their hopes on the idea that once Trump takes office, he will come around to their point of view on the Kremlin. “It’s good to question our intelligence community. I have no problem with him being skeptical. But just listen with an open mind,” Graham said, offering Trump unsolicited advice for his Friday briefing. “When General Mattis said ‘Give me a pack of cigarettes and a cold beer; I can get more information than waterboarding,’ that impressed the president-elect,” Graham added, referencing Trump’s pick for defense secretary, James Mattis. “I’m hoping after Friday he will be more convinced.”

Senior Republicans, including Senate Majority Leader Mitch McConnell (Ky.), have stressed the need for investigations into Russia’s activities, expressing support for existing sanctions as well as the pursuit of additional punitive measures.

McCain, Graham and Sen. Marco Rubio (R-Fla.) all said Wednesday that they were in discussions with Sen. Benjamin L. Cardin (Md.), the Senate Foreign Relations Committee ranking Democrat, to join forces behind a bill, expected this week, to impose sanctions against Russia. The sanctions in Cardin’s bill address Russia’s alleged election-related hacks, its interference in Ukraine and its conduct in the Syrian war, which Secretary of State John F. Kerry said last year warrants a war-crimes investigation.

The bipartisan heads of the Senate’s Foreign Relations, Armed Services and Intelligence committees met Wednesday to coordinate how to conduct the Russian-hacking investigation over the next weeks and months. After the meeting, Democrats expressed hope that Trump’s attacks on the intelligence community would not complicate their efforts.

“The most important role of the intelligence community is to speak truth to power,” said Sen. Mark R. Warner (Va.), lead Democrat on the Intelligence Committee, noting that Trump’s “rather dismissive attitude of the intelligence community” concerns him. “There is broad-based bipartisan concern that we’ve got to do this investigation in an appropriate manner as quickly as possible,” Warner added.