House Speaker Nancy Pelosi opened six hours of impeachment debate by saying that "today is a national civics lesson, though a sad one."

The scene played out across the nation’s polarized landscape Monday as about a dozen of the 31 most vulnerable House Democrats climbed off the fence and into the ranks of lawmakers who will vote for formal abuse and obstruction charges against Trump this week.

The president himself has remained defiant amid the process.

Fewer than one-third of the 23 Democrats vying for the nomination are issuing calls to start the impeachment process, citing evidence in special counsel Robert Mueller’s report they believe shows Trump obstructed justice.

More Democrats are calling - and more loudly - for impeachment proceedings against U.S. President Donald Trump after his latest defiance of Congress by blocking his former White House lawyer from testifying.

Democratic voters are clamouring for their party to do something about Trump, but impeaching him is a dangerous move, writes Jackson Proskow.