He can apologize all he wants, but Devin Nunes's ill-considered move this week to leapfrog his panel colleagues by informing the White House about surveillance of the Trump team has already fractured his committee, deepened doubts about its fairness and amplified calls for an independent probe.

Trust in Nunes, the chair of the U.S. House intelligence committee, has splintered after he shared with the Trump administration a report from the U.S. intelligence community that legal, broad surveillance activities might have "incidentally collected" communications with the president.

As the ranking Democrat on the committee, the expectation would have been that congressman Adam Schiff of California would be briefed first on the matter, along with Nunes's Republican committee colleagues. Instead, Schiff learned of the intelligence intercepts via a media statement.

House intelligence committee ranking Democrat Adam Schiff said Nunes presented information to the press and to the White House before the committee had a chance to vet whether it's significant. (Jim Bourg/Reuters)

Schiff slammed the chairman for acting as if he were a "surrogate of the White House."

"You don't take information that the committee hasn't seen and present it orally to the press and to the White House before the committee even has a chance to vet whether it's even significant," he fumed to reporters on Wednesday.

Cries from the Democratic side will likely grow louder for an independent investigation, says Mark Harkins, a congressional expert with the Government Affairs Institute at Georgetown University. A censure motion or other disciplinary action for Nunes might be introduced on the House floor.

What the American people have found so far is that no longer does Congress have the credibility to handle this alone. - U.S. Senator John McCain

"Being that he's supposedly the chairman of the investigative committee but went directly to the executive branch, that leads to concerns as to whether he can properly execute the oversight role that Congress has over the executive branch."

Speaking to CNN, Elijah Cummings, the top Democrat on the House oversight committee, suggested that Nunes himself should become the subject of an investigation.

Senator John McCain, a fellow Republican, called the committee's integrity into doubt and told NBC News it was a "bizarre situation."

"What the American people have found so far is that no longer does Congress have the credibility to handle this alone," he said.

Nunes apologizes

Nunes, a congressman from California, was a member of U.S. President Donald Trump's transition team. He apologized on Thursday for the unusual briefing, given his role as chair of the chief investigative panel probing Russia's alleged interference in the 2016 election.

It didn't appear to be enough. Speaking to reporters on Thursday, Democratic congresswoman Jackie Speier, who sits on the House panel, said it was a "grave question" whether the committee should continue to have faith in their chairman.

"Over the next few days, we are going to assess whether or not we feel confident that he can continue in that role," she said.

Nunes's actions weren't just a breach of decorum, say veteran staffers of former House and Senate intelligence committees.

"It was a rupture in a relationship with the committee in a highly sensitive topic," says Mark Lowenthal, who served as a Republican staff director of the House permanent select committee on intelligence during the Bill Clinton administration.

Lowenthal believes Democrats will be wary of dealing with him further if they suspect Nunes, a staunch Trump ally on Capitol Hill, might have divided loyalties. He expects dysfunction can also bleed through into the House committee's affairs.

The morning after the Nunes uproar, Trump's campaign team sent out an email blast with a one-word subject line: 'Vindicated.' (Justin Sullivan/Getty Images)

When a bipartisan committee comes apart in such a way, he said, "it becomes very, very unpleasant; trust is lost and it's hard to get any work done.

"So yes, you can apologize, but the damage is done."

Were he more politically astute, Lowenthal says, Nunes would have presented the intelligence report to Schiff regarding possible collection of surveillance of Trump, then shared his intentions to approach the president.

Collateral effect

There may also be a collateral effect in the separate Senate intelligence committee into the Trump-Russia matter, which is to be chaired by Senator Richard Burr. The North Carolina Republican could be constricted by the fallout from his counterpart in the House committee.

That could be a positive outcome, says Gary Schmitt, a former staff director for the Senate select committee on intelligence.

"You'll see an effort by the [Senate intelligence] committee itself to be forced, in a way, to remain as bipartisan as possible, because its reputation is at stake," Schmitt says. "Nunes has put them in a position where if they don't do their job in a very bipartisan way, the reputation of the institution suffers, and they suffer reputationally."

Demands to form a new special committee such as the independent inquiry that looked into the Benghazi embassy attacks in 2012 are "inevitable," Schmitt says.

The Trump administration, meanwhile, has seized upon the latest intelligence revelations by Nunes as validation of the president's debunked claims that the Obama administration ordered Trump Tower to be wiretapped.

When pressed further, though, Nunes stressed it was "possible" that routine U.S. surveillance of foreign targets — and unrelated to Trump — might have also scooped up some of the president's communications in the process. There remains no evidence that any wiretapping occurred, Nunes said.

Trump nevertheless wasted no time spinning the development in his favour. The morning after the Nunes uproar, Trump's campaign team issued a new email blast imploring subscribers to stand with the president against the scourge of so-called fake news. The email had a one-word subject line: "Vindicated."