Chuck Schumer, the Democratic leader in the Senate, said the Republican rules were a “national disgrace” designed to help increase the chances of Mr Trump’s acquittal.
“A trial without evidence is a cover-up”, Mr Schumer said, calling the rules “designed by President Trump, for President Trump” and pledging to table amendments to change them.
“My colleagues, the eyes of the nation, the eyes of history, the eyes of the founding fathers are upon us,” Mr Schumer said. “History will be our final judge. Will senators rise to the occasion?”
But Mr McConnell, the Republican leader, argued his rules were similar to those used in the trial of Mr Clinton, a Democrat, and accused his political opponents of hypocrisy.
“Fair is fair. The process was good enough for President Clinton and basic fairness dictates it ought to be good enough for this president as well,” Mr McConnell said.