Donald Trump's tumultuous term is ending as it began amid chaos and controversy after becoming the first president to be impeached twice in a devastating bipartisan rebuke that could see him barred from ever returning to the White House.

As Mr Trump for the first time condemned the violent mob that stormed and sacked the Capitol in his name a week ago, Washington was thrown into further tumult as one of the president's staunchest enablers and supporters opened the door to convicting him in a Senate trial on inciting insurrection.