In the battle over public opinion on impeachment, U.S. President Donald Trump has gone to a familiar playbook: Try to discredit the accusers, offer alternative theories, and flood social media with attacks and complaints.

Trump is banking on what worked in helping to shape public opinion around special counsel Robert Mueller's Russia investigation, though it could prove more difficult this time around.

Crisis communications experts who spoke with CBC News say Trump's reliance on himself as primary spokesperson and defender has worked before but has the potential to backfire by projecting weakness rather than strength.

"He looks like he's under siege. He looks like he's playing defence, not offence," said conservative author and columnist Tom Basile.

"If he's going to survive this and shape this in the way he was able to shape the Mueller investigation and change public opinion, [the White House] is going to need a more robust communication strategy."

“The congratulatory phone call with the Ukrainian President was PERFECT, unless you heard Liddle’ Adam Schiff’s fraudulently made up version of the call. This is just another Fake News Media, together with their partner, the Democrat Party, HOAX! —@realDonaldTrump

Key to that strategy, experts say, is creating a war room — a dedicated team of lawyers and communications professionals to deal with the deluge of news coming from the scandal relating to a July phone call with Ukrainian President Volodymyr Zelensky in which Trump asked that Zelensky investigate former vice-president Joe Biden and his son, Hunter.

That call, coming days after Trump put $391 million in military aid to Ukraine on hold, has Democrats accusing the president of trying to coerce a foreign leader into investigating a political rival and interfering in the 2020 U.S. election.

A week after House Speaker Nancy Pelosi announced an impeachment inquiry, multiple reports have described a White House still scrambling internally to come up with a coherent and unified strategy to get out its message and defend the president.

The pushback got off to a rough start when the White House accidentally sent out talking points defending Trump to rival Democrats, who promptly tweeted them out.

Having a war room helped President Bill Clinton weather an impeachment storm in the late 1990s, said Erik Smith, who worked as press secretary for Democratic House minority leader Dick Gephardt during that time.

Smith said the biggest difference between how Trump and Clinton approach crisis communications is that, for the most part, Clinton let others handle his impeachment defence. About a dozen people, half of them lawyers, focused solely on the crisis.

U.S. President Bill Clinton speaks to the nation following his acquittal by the U.S. Senate on impeachment charges on Feb. 12, 1999. The Senate voted to reject both counts of impeachment presented by the House of Representatives. (Reuters)

"Clinton was able to compartmentalize, so while he had a team of lawyers and communications professionals focused on impeachment, you never heard him talk about it," Smith said.

"It looked to the public as though it was not inhibiting or slowing down the progress Clinton was making on fixing the economy or improving the state of the country."

Trump, Smith observes, is doing the opposite.

"He's making it as big an issue, if not bigger, than the House Democrats."

He noted that while Trump has brought up jobs and other positive news for his administration, it's been drowned out by the sheer volume of his own impeachment-related talk.

....People, their VOTE, their Freedoms, their Second Amendment, Religion, Military, Border Wall, and their God-given rights as a Citizen of The United States of America! —@realDonaldTrump

Basile says the current disarray is part of a consistent lack of message discipline that's been a feature of the administration. It's driven by a president who upends any effort to keep messaging focused and on track, he said.

"Trump is excellent at muddying waters, but I think they have the ability to be a lot more effective," Basile said.

Charles Fulwood, who teaches emergency and crisis communications at the Washington, D.C., campus of Johns Hopkins University, said the challenge in coming up with a strategy is that Trump lacks the discipline or the humility to stick with one.

"His strategy is always by the gut, no matter what the facts and circumstances are, and since that's worked for him most of his career, at least from his point of view, he doesn't see any reason to abandon that now."

In a Sunday morning Twitter storm, for example, Trump posted or retweeted 25 impeachment-related messages before 8:30 a.m.

From attacking the chair of the House intelligence committee, Adam Schiff, to warning of a possible civil war and a coup d'état, the defence from the president and others in the administration has varied. But talk of creating a war room seems to have been dismissed by some Trump advisers.

"We just went through what is a real war with Bob Mueller, without the war room, and came out fine. This is a skirmish in comparison," said Trump's personal attorney, Jay Sekulow, on his radio show Monday.

With a large war chest that's been building since his first day in office, some reports have suggested Trump's 2020 re-election team may try to take the lead on impeachment messaging.

Basile says Trump should establish a war room and expand the roster of people defending him, stretching beyond politicians to include legal scholars, impeachment experts and others. Then focus on governing, framing impeachment as politically motivated by the Democrats.

"Makes Democrats look small," Basile said. "Americans like to see their president doing something and they don't want to see paralysis on the part of any branch of government."

The Mueller playbook

Calling impeachment a partisan plot is a recurring theme in Trump's tweets, something Smith said could be part of a strategy informed by Trump's experience with the Mueller investigation.

Trump is portraying impeachment as a Democratic assault on his presidency, a Witch Hunt 2.0., he said.

"There's something in his language about victimhood that resonates with his base," Smith said.

He's also chosen his targets carefully, Smith said, including focusing attention on Schiff, the de facto head of impeachment proceedings, whom Trump sees as a less sympathetic figure than Pelosi.

Charles Fulwood, the crisis communications expert from Johns Hopkins University, said that what worked for Trump during the Mueller investigation — hammering home a consistent message that attacked the credibility of the special counsel — may not serve him well during impeachment.

He said the Ukraine call scandal is much easier to understand than Mueller's multi-faceted investigation into Russia's interference in the 2016 U.S. election and its possible ties to the Trump campaign.

It's also possible, he said, that some Americans who may have initially been inclined to give Trump the benefit of the doubt may grow exhausted of the president and his scandals.

"There always seems to be some hint or scent of corruption or abuse of power that surrounds him," Fulwood said, noting polls are suggesting increased support for impeachment proceedings.

He points out that even Fox News, often an echo chamber for Trump talking points, has seen anchors in its news operation treat Trump's talking points more critically than ever.

Karen Hult, a political science professor at Virginia Tech, says an argument can be made that it's more difficult for the president this time because much of what Mueller was initially investigating with Russian interference didn't directly involve Trump.

"The facts on the ground are different now," she said. "He's on the telephone."

White House legal counsel Emmet Flood, right, was part of Clinton's impeachment defence team in the late 1990s and later helped Trump with his response to the Mueller investigation. He left the White House in the summer and hasn't been replaced. (Jonathan Ernst/Reuters)

Hult points out that Trump doesn't have a deep bench to call upon to defend him.

Emmet Flood, for example, who was part of Clinton's impeachment team and later helped Trump with his response to the Mueller investigation, left the White House in the summer and wasn't replaced.

"It's not just the turnover, it's also that not all the people have been replaced and you have new people in the positions trying to figure out where the kitchen is," Hult said. "All of that is hard — and then the crisis strikes."