But President Donald Trump did not immediately fire the adviser, Michael T. Flynn, over the apparent lie or the susceptibility to blackmail.
Sally Yates, former Deputy Attorney General, testified on Monday that former national security adviser Michael Flynn had been compromised by his ties to Russian Federation, and as a result, was vulnerable to blackmail.
The president's national security adviser, she said, had lied to the vice president about his Russian contacts and was vulnerable to blackmail by Moscow. Trump fired Yates that same day, reportedly for refusing to defend an executive order that closed us borders to refugees and immigrants from seven predominantly Muslim countries. Meanwhile, it took 18 days for the White House to fire Flynn after Yates first told McGahn about his Federal Bureau of Investigation interview. But between the information she disclosed and the behavior of the President of the United States following the hearing, it's clear that this scandal is far from over - and that is, as Maddow said on Monday, "very, very bad news for this White House".
White House officials, including Vice President Mike Pence, had insisted that Mr Flynn did not discuss US-imposed sanctions with Mr Kislyak during the presidential transition period.
Lawmakers said after the hearing that Yates had revealed a number of new details they had not known before, particularly about her conversations with the White House on Flynn.
"Logic would tell you that you don't want the national security adviser to be in a position where the Russians have leverage over him", she said.
Trump has repeatedly called the investigations of possible coordination between his campaign aides and Russian Federation "fake news" and, last week, said it may have been China that was behind the hacking.
Probes by several congressional committees into Russian election meddling have been bogged down for weeks amid accusations by Democrats that Republicans have stalled progress to protect the White House.
Trump moved to distance himself from his former adviser's troubles Monday, tweeting that it was the Obama administration that gave Flynn "the highest security clearance" when he worked at the Pentagon. Trump made no mention of the fact that Flynn had been fired by the Obama administration in 2014. Current and former officials said that in November, President Barack Obama warned the president-elect not to hire Flynn.
Mr Trump's press secretary Sean Spicer said in response that if Mr Obama "was seriously concerned" about Mr Flynn's connections to Russian Federation or other foreign countries, he should have withheld Mr Flynn's security clearance.
In a second meeting the following day, McGahn asked Yates whether it would be possible to look at the evidence - presumably transcripts of wiretapped conversations - that was driving the DOJ's concerns about Flynn.
Clapper testified on Monday before a Senate judiciary subcommittee about Russia's interference in the 2016 election, the Washington Post reports.
Senator Ted Cruz, an artful debater, had some pointed questions for former acting attorney general Sally Yates at today's hearing.
"Sally Yates made the fake media extremely unhappy today - she said nothing but old news!" Yates told him that it wasn't just Flynn's fudging about the Russian Federation calls that troubled her and the two senior national security officials who she consulted before taking up the issue with the White House.
- Jennifer Epstein (@jeneps)Never really believed there was collusion between Trump & Russia. until he just put that twitter header up. Yet questions remain about whether the Republican-led committees can conduct truly independent investigations.