WASHINGTON—For nearly three weeks, President Donald Trump knew his national security adviser, Michael Flynn, had lied to top administration officials, including the vice-president, about conversations with the Russian ambassador to the United States, but he kept Flynn on as a pivotal member of his team.

During that time, Flynn briefed the president on global issues, sat in on phone conversations Trump held with a variety of world leaders, helped craft foreign policy as a trio of allies — the prime ministers of Britain, Japan and Canada — visited Washington, and helped formulate the response Saturday to a North Korea ballistic missile launch.

He was seated in the front row at a news conference Trump held with Prime Minister Justin Trudeau on Monday.

But between that news conference Monday afternoon and 10 o’clock that night, Trump “lost trust” in Flynn over his lying about his contacts with Russian officials and what White House press secretary Sean Spicer called “a host of other issues” and demanded Flynn’s resignation.

On Tuesday, Spicer declined to say what those other issues might have been, and he did not explain why it took the president more than two weeks to determine that Flynn was no longer worthy of being trusted.

“I’m not going to get into the specifics of what the president’s thinking was, but I will just say ... that it was an evolving and eroding process,” Spicer said.

In the White House’s retelling of Flynn’s stunning downfall, his error was not that he discussed U.S. sanctions with the Russian before the inauguration — a potential violation of a rarely enforced law — but the fact that he denied it for weeks, apparently misleading Vice-President Mike Pence and other senior Trump aides about the nature of the conversations. White House officials said they conducted a thorough review of Flynn’s interactions, including transcripts of calls secretly recorded by U.S. intelligence officials, but found nothing illegal.

Trump’s decision to fire Flynn came less than two hours after the Washington Post published a story detailing that the Justice Department, under acting attorney general Sally Yates, had warned the White House that Flynn had mischaracterized his conversations with the Russian ambassador, whose phones are routinely tapped.

The Justice Department warning said that, contrary to Flynn’s account, the two men did discuss sanctions that president Barack Obama had imposed on Russia on Dec. 29 to punish Russia for its alleged efforts to influence the outcome of November’s presidential election.

Trump kept Pence in the dark and waited another two weeks before ousting Flynn. Pence, who had vouched for Flynn in a televised interview, is said to be angry and deeply frustrated.

The Trump administration was preparing to replace Flynn as early as last week with Robert Harward, a senior White House official said Tuesday. Harward is a retired navy vice-admiral who once served under James Mattis, now defence secretary, at U.S. Central Command.

Former CIA director David Petraeus and retired Lt.-Gen. Keith Kellogg, who has temporarily stepped into the role, are also under consideration.

The FBI is investigating Flynn’s contacts with Russia and questioned him last month, according to news reports. Democrats in Congress, who called for a bipartisan investigation, quickly questioned why Trump delayed taking action.

Flynn defended himself in an interview with The Daily Caller. He insisted he broke no rules in his talks with the Russian ambassador, but was concerned about leaks of classified information.

“I haven’t been fighting back because I’m not that kind of guy,” the publication quoted Flynn as saying. “This is ridiculous. It’s so out of control. I’ve become an international celebrity for all the wrong reasons.”

Missouri Democrat Claire McCaskill of the Senate’s armed services committee, said it was important for the Senate and the public to know exactly how long the Trump administration had known that Flynn had lied about his dealings with Russians, yet failed to act. She said Flynn had to be brought in to testify.

“Russia is not our friend. Putin is not our friend. And this is not a matter of just Flynn,” she said.

Even Republicans acknowledged that more information was needed.

“I’m open to any suggestions that are constructive and not necessarily politically motivated,” said Sen. Thom Tillis of North Carolina.

Loading... Loading... Loading... Loading... Loading... Loading...

The White House shakeup, less than one month into Trump’s tenure, marked another jarring setback for a new administration already dealing with tensions among top aides and a legal fight over the president’s travel ban order. Flynn’s firing also heightened questions about the president’s friendly posture toward Russia and his admiring comments about Russian President Vladimir Putin and his ties to that country.

The president has said he would consider lifting the sanctions imposed against Russia over its 2014 annexation of Crimea from Ukraine. This month, the White House loosened financial sanctions against Russia’s powerful security agency that the Obama administration had imposed as punishment for Russia’s meddling in November’s presidential election and for the Crimea annexation.

Flynn is the third Trump adviser forced out over links to the Russian government of President Vladimir Putin. Paul Manafort, Trump’s former campaign manager, was first. Carter Page, an early foreign policy adviser to the campaign, also left amid scrutiny over his Russian ties.

With files from The Associated Press and Bloomberg

Read more about: