Trump has so far used the claim with nine people who had all been arrested, indicted or admitted to committing federal crimes.
"It's lack of character among people on these committees. Just a lack of character," MSNBC host Joe Scarborough said.
"This is the country I have served and defended, that all of my brothers have served and here, right matters," the lieutenant colonel told the House Intelligence Committee.
The former ambassador to Ukraine was attacked on Twitter by President Donald Trump as she testified before the House Intelligence Committee.
"The chairman refused to allow us to put these into the record with unanimous consent," Stefanik said, amid Friday's impeachment hearing.
GOP Minority Leader Kevin McCarthy railed against Adam Schiff Sunday, accusing him of single-handedly dictating the impeachment inquiry he described as a "calculated coup."
Rep. Devin Nunes demanded that Schiff answer questions from Republicans privately even though he was one of the most vocal critics of the impeachment inquiry's alleged lack of transparency.
Giuliani said if Schiff is removed and a "neutral person" is put in his place as chairman of the House committee, then he may consider cooperating with Congress.
The president in recent days, by way of tweet storms and press conferences, has relentlessly bashed the Ukraine whistleblower and denied any wrongdoing during a phone call in which he pressured a foreign leader to investigate a political opponent.
"This is not considered by the intelligence community...to be a frivolous matter or something that was overblown," Andrew McCabe said.
Mueller will appear before the House Judiciary Committee for three hours and before the House Intelligence Committee for two hours.
"There may be grounds for removal from office or there may be grounds for indictment after he leaves office that the Congress discovers," Schiff said.
"I didn't think this summit went well for the president at all, more importantly for the U.S. national security," Mike Rogers, a former Republican congressman said.
President Donald Trump's former "fixer" Michael Cohen will testify before three congressional committees this week.
Adam Schiff, chairman of the House intelligence committee, said the panel would probe the financial interests of Trump, his family and allies to determine if those interests are driving the president's or his administration's decisions.
The DOJ gave house Republicans thousands of documents.
"We see no reason to dispute the conclusions," Senate Intelligence Committee Chairman Richard Burr stated.
Under pressure, the Justice Department provided access to the original document that launched the investigation into Russian election interference.
Trump welcomed the news.
"Politics beat a desire for the truth," former Attorney General Eric Holder said, slamming House Intelligence Committee Republicans for unilaterally shutting down the Trump-Russia probe.
Hicks resigned from her role on Wednesday.
After a closed-door interview with White House communications director Hope Hicks, Representative Dennis Heck (D-WA) declared: "We got Bannoned!"
Representative Adam Schiff said House Intelligence Committee Chairman Devin Nunes changed a controversial memo after the panel reviewed it.