“It is going to be challenged,” said Mr. Manchin, who sided with Mr. McConnell and Senate Republicans to block fellow Democrats from rewriting the Senate rule book.
Senator Chuck Schumer, Democrat of New York and the majority leader, said as much recently when he suggested his party could try again to change the filibuster rules for voting rights legislation if Democrats wind up in control of the Senate, the House and the White House next year.
“When people attempt — courts or legislators — to take away voting rights, particularly of the most disenfranchised people, we have an obligation to do everything we can to restore those voting rights,” Mr. Schumer said after the decision by Ms. Sinema, now an independent, to relinquish her seat given her daunting re-election challenge.
Once rarely used, the filibuster has become a routine part of Senate life and has kept significant legislation bottled up. It was central to efforts to blockade civil rights legislation in the past but in recent years has ensnared gun control, health care and other social policy measures.