WASHINGTON — Two minutes into Monday’s historic House Judiciary Committee hearing into the impeachment of President Trump — even before Representative Jerrold Nadler, the chairman, issued the customary call for decorum — a protester, screaming that Mr. Nadler was committing treason, was dragged out of the grand columned hearing room by the Capitol Police.

It was the first clue that this was not going to be a somber session befitting the gravity of the occasion.

The hearing was intended as an opportunity for Democrats to lay out their case that Mr. Trump had violated the Constitution with a “brazen” scheme to enlist Ukraine to interfere in the 2020 election — and for Republicans to respond. But it quickly devolved from a staid courtroom drama into a raucous, gavel-banging, partisan verbal melee.

“You will not shout out — not shout out in the middle of testimony,” a frustrated Mr. Nadler exclaimed at one point, bringing the gavel down in a fruitless effort to shut down Republican parliamentary objections.