A dramatic protest or a desperate attempt to hijack the news cycle? However you look at it, when close to 40 Republicans burst into a closed impeachment hearing on Wednesday, it was an unprecedented moment that some experts warn has pushed the bounds of legitimate partisan attacks.

Florida Rep. Matt Gaetz, one of President Donald Trump's most loyal defenders in Congress, led the group of Republicans as they forced their way into what's known as a sensitive compartmented information facility, or SCIF, to disrupt a closed deposition from a Pentagon official in the ongoing presidential impeachment inquiry.

"The American people deserve a public and open process," Rep. Mo Brooks of Alabama said outside the hearing room, moments before the Republicans barged in.

The Republicans said the storming of the SCIF was necessary to expose what they call the secretive Democrat-led hearings that have denied the president transparency and a chance to face his accusers.

A picture from above as Gaetz speaks during a news conference alongside House Republicans on Capitol Hill. They're calling for transparency regarding the impeachment inquiry into President Donald Trump. (Alex Wroblewski/Getty Images)

The Democrats are investigating whether Trump used the power of his office to pressure Ukraine into delivering political favours to help his chances in the 2020 election.

"By golly, if they're going to do it, do it in public," Brooks said. "Don't hide it from the American people. Show your face where we can all see the travesty that you are trying to foist on America and the degradation of our republic that you are engaged in."

Attacking process not substance

But the attack on the impeachment inquiry process, rather than the substance of what has emerged so far, struck some historians as being deliberately disingenuous.

The protest came the day after testimony from the top U.S. diplomat in Ukraine, Bill Taylor, in which he reportedly described various examples of Trump directing staff to pressure Ukrainian officials into investigating his political rival, Democratic presidential hopeful Joe Biden.

Among the Republicans complaining about secrecy were at least eight members who sit on the three committees investigating impeachment. They have access to information in the hearings, the ability to question witnesses and can report the content of the hearings to party leadership.

"They never outright lied, but they certainly conveyed a message that was very different than reality and that is classic gaslighting," said Heather Cox Richardson, a history professor at Boston College.

Bill Taylor, the top U.S. diplomat in Ukraine, arrives to testify at a closed-door deposition as part of the impeachment inquiry. (Carlos Jasso/Reuters)

For Penn State law professor Lance Cole, an expert in congressional investigations, the protest was "completely asinine."

"This is the way congressional investigations are conducted and have been forever. You take private depositions and then you call hearings with witnesses," said Cole, co-author of Congressional Investigations and Oversight: Case Studies and Analysis.

In the mid-1990s, Cole was minority deputy counsel for the Whitewater investigation, a probe into real estate dealings involving President Bill Clinton. He says they held close to 250 private depositions, involving lawyers from both parties, before moving on to public hearings.

The secrecy, he says, is necessary to prevent witnesses from comparing notes and tainting future testimony.

He acknowledges that impeachment is as much a political process as a legal one, but says this type of attack could do short- and long-term damage to the constitutional system.

"It contributes to an atmosphere of chaos and an atmosphere of the institutional norms are breaking down, that the system is rigged, the system is flawed, the system is not working," he said.

To many, the storming of the SCIF on Wednesday appeared to be a direct response to Trump saying a few days earlier that Republicans in the House weren't doing enough to defend him from impeachment charges. Trump also reportedly had advanced knowledge of what the Republicans had planned.

Cole warned that attacks seemingly directed by the executive branch against the legislative branch take the U.S. into dangerous territory when it comes to the constitution.

Politically necessary

But with so much at stake, controlling the message is vital in an impeachment process, particularly since many citizens don't understand exactly what's happening, said Republican strategist Ford O'Connell.

"Everyone's political survival, on both sides of the aisle, depends on how this is perceived by the American public," said O'Connell, who points out that Republicans were able to dominate a news cycle with their actions.

He accuses the Democrats of providing reporters with selective leaks from the hearings to help push down the president's poll numbers and increase support for impeachment, without giving the full story.

"Most people are a blank slate, and both sides are trying to lay their narrative down. Most people don't know this is happening behind closed doors and they don't follow the ins and outs of politics like folks in the beltway," said O'Connell, who worked on John McCain's 2008 presidential campaign.

Republican Rep. Mark Meadows enters a secure area as deputy assistant secretary of defence Laura Cooper testifies in a closed-door deposition. (Yuri Gripas/Reuters)

He said the Republican tactics are aimed at a small slice of persuadable independent and swing-state voters.

He pointed to a recent New York Times/Siena College survey of voters in Pennsylvania, Michigan, Florida, North Carolina, Wisconsin and Arizona that suggests only 43 per cent support impeachment and removal of Trump from office.

"We're basically watching a show unfold that is essentially for the benefit of probably less than 10 per cent of the voters in six states," O'Connell said.

Shattering the norms

Wednesday's deposition of Pentagon official Laura Cooper eventually took place, five hours after it was scheduled to begin.

But in their attempt to defend the president at all costs, Republicans are continuing to show glimpses of tactics used in authoritarian regimes, said historian Ruth Ben-Ghiat of New York University.

"I don't see it as a distraction. I see it as a continuation of this contaminated, lawless culture that the Republicans have adopted in order to protect themselves and Donald Trump," she said.

Republicans are on the defensive, and thus, they've become the aggressors. - Ruth Ben-Ghiat, historian

The idea of staging the intervention in an aggressive way is one problematic thing, but consciously violating norms of national security — by bringing cellphones into a secured room — is another, she said.

"It kind of shows that nothing is sacred anymore, and every rule and norm can be broken in the interest of ideology, which is the cult of Donald Trump."

That the Republican members who took part in the protest are the president's most staunch allies in Congress comes as no surprise to her.

"Defending the president is defending themselves," she said. "And so, saving him is also saving themselves."

Beyond partisanship

Heather Cox Richardson, the history professor at Boston College, acknowledges that partisan attempts to game the system and win the messaging battle are nothing new.

From Sen. Strom Thurmond's 24-hour filibuster in 1957 to try to prevent the passage of the Civil Rights Act, to Senate majority leader Mitch McConnell taking the unprecedented step in 2016 of refusing to hold a hearing for President Barack Obama's Supreme Court nominee, Merrick Garland.

But she says what happened on Capitol Hill this week was a shocking escalation.

"[The Republicans] knew perfectly well they were conveying a message that was a lie and they did it anyway," she said.

"These, therefore, are people who don't believe in the process and are willing to lie to their supporters in order to affect the outcome of something that's of grave importance to the nation."

Having worked on investigations under presidents Clinton and George W. Bush, law professor Lance Cole says partisanship is always in play — the difference now is how far Trump will take it.

"He's sending directives that President Clinton would never have imagined, that President Bush would never have imagined," he said. "The difference is Trump and the way he's directing the executive branch."

Ben-Ghiat warned the storming of the SCIF may be a sign of more extreme tactics to come.

"I feel like in the last few weeks, things have become exacerbated. Republicans are on the defensive, and thus, they've become the aggressors."