The House Intelligence Committee is poised to question Steve Bannon, the onetime confidant to President Donald Trump, following his spectacular fall from power after accusing the president's son and others of "treasonous" behavior for taking a meeting with Russians during the 2016 campaign. He continued to speak with Trump and tried to promote the president's agenda.
Bannon is said to have expressed "regret" over the remarks.
He was reportedly subpoenaed by former Federal Bureau of Investigation director Robert Mueller, who is leading an inquiry into alleged collusion with Russian Federation during the 2016 election campaign.
Sources told the Fox News reporter that Bannon was told by the White House not to answer lawmakers' questions about the administration or the Trump transition, although he did not claim executive privilege.
News of the subpoena comes on the same day Bannon testified, in a closed-door hearing, before investigators on the House Intelligence Committee who are scrutinizing Russia's election meddling. After all, the quotes from Bannon in Wolff's book were what led to the falling out between he and the Trump family, and contributed heavily to him parting ways with Breitbart, which he had run for years.
The subpoena may have been a negotiating tactic to convince Mr Bannon to sit down with Mr Mueller for a less-formal interview in the special counsel's offices, legal experts said.
The June 2016 meeting involving Trump's son Donald Jr, son-in-law Jared Kushner, then campaign chairman Paul Manafort and Russian lawyer Natalia Veselnitskaya at Trump Tower in NY.
Former Trump ally Steve Bannon has seen his support among Republicans crater to new lows.
He has since regretted the comments and has been fired from Breitbart News as part of the fallout.
Bannon also told Wolff that he believed that Mueller's investigation would eventually focus on money laundering. "We've been cooperating fully with these ongoing investigations and encourage the committees to work with us to find an appropriate accommodation in order to ensure Congress obtains information necessary to its legitimate interests".
Lewandowski said he hopes Democrats finally come to a "realization" that there was no Trump-Russia collusion, adding the Clinton campaign was "a very different story".