It's been reported in history that impeachment can happen when one leaves office. This is what someone has said. Now...I'm digging and I'm not sure if I can find it. Ive found someone actually arguing the opposite. Sauce: https://www.legislativeprocedure.com/blog/2021/1/8/latest-impeachment-effort-not-possible-under-rules "The Constitution defines who is subject to impeachment (Article II, section 4). It stipulates, "The President, Vice President and all civil Officers of the United States, shall be removed from Office on Impeachment for, and Conviction of, Treason, Bribery, or other high Crimes and Misdemeanors." The Senate must vote separately to bar an impeached official from office. That vote, unlike the vote to convict, requires a simple majority. But that vote is not in order until after the Senate has voted to convict the official based on the articles of impeachment. The Senate cannot remove someone from office if they are not in that office. And absent a conviction vote, the Senate cannot bar someone from holding future office. The consequences of giving Congress this power would be to allow it to bar private citizens from holding office preemptively."
This leads me to believe that Congress is trying to panic vote Trump out of office before the 20th..HOWEVER. They won't get an impeachment hearing. It wouldnt be till the 20th before they can get their ducks in a row for impeachment. WHY is congress pushing for impeachment?
They're creating the narrative that Trump has gone made and they need to protect the country by taking the nukes away and impeaching/removing him asap. When things start happening, arrests/indictments are announced, etc, they can say 'see, we told you he's mad!' It's just propaganda from those in a death spiral at this point.