President Donald Trump suggested Thursday that he may block officials from listening in on his calls with foreign leaders after a whistleblower's complaint about his call with the Ukrainian President ultimately led to his impeachment.

Former White House chief of staff John Kelly said Wednesday that Lt. Col. Alexander Vindman, a key witness in President Donald Trump's impeachment inquiry, was right to raise concerns about Trump's July call to Ukraine's president, The Atlantic reported Thursday.

Retired Ambassador Marie "Masha" Yovanovitch -- a highly respected career diplomat who unwittingly became one of the central figures in the impeachment drama -- warned about the degradation of the State Department and took veiled jabs at the Trump administration in her first public remarks since leaving the diplomatic service.

Attorney General William Barr has agreed to testify before the House Judiciary Committee next month, the panel's chairman Jerry Nadler said Wednesday, giving them a forum to press the attorney general on the sentencing of Roger Stone and other controversies that have emerged in the aftermath of President Donald Trump's impeachment trial.

Republican Sen. Susan Collins of Maine, who voted to acquit President Donald Trump at his impeachment trial, said Wednesday that her acquittal vote was "not based on predicting (Trump's) future behavior," following previous comments she made saying Trump had "learned from this case."

Eight days removed from Donald Trump's acquittal on both articles of impeachment, the President is leaning heavily into a revenge tour against his political enemies -- an effort that makes Maine Sen. Susan Collins' claim that Trump had learned his lesson from the impeachment proceedings all the more outlandish.

CNN's Daniel Dale fact-checks President Donald Trump's comments he made during a rally in New Hampshire ahead of the Democratic primary.

The two impeachment witnesses that President Donald Trump fired Friday were quietly planning exits of their own, multiple people tell CNN.