Mitch McConnell, minority leader at the US Senate, warned Democrats on Tuesday that doing away with the chamber's filibuster rule would lead to a "completely scorched earth" Senate, in which Democratic President Joe Biden would have a much harder time moving his agenda.
Democrats, who narrowly control the Senate, in recent weeks have voiced more support for the idea of eliminating the custom that requires 60 votes to pass most legislation in the 100-seat chamber.
They have said the move may be necessary to pass measures, including a House of Representatives-approved bill intended to make it easier to vote and other priorities of Mr Biden.
"This chaos would not open up an express lane to liberal change. It would not open up an express lane for the Biden presidency to speed into the history books. The Senate would be more like a 100-car pile-up. Nothing moving," Mr McConnell, a Kentucky Republican, said on the Senate floor.
"Nobody serving in this chamber can even begin ... to imagine what a completely scorched-earth Senate would look like," he added.
The Senate is currently split 50-50 between Democrats and Republicans.
Chuck Schumer, majority leader at the Senate, said on Sunday Democrats hoped to work with Republicans to move forward legislation intended to improve voter participation, renew US infrastructure and make sections of Mr Biden's $1.9 trillion Covid-19 relief bill permanent.
But he said Democrats were determined to overcome Republican opposition and added that all options were on the table.
Stacey Abrams, an influential voting-rights advocate and former Democratic candidate for governor of Georgia, also called on Sunday for the Senate to exempt election reform legislation passed by the House over Republican opposition from the filibuster procedural hurdle.
