It’s not in the Constitution; it’s an arbitrary Senate rule, and the Senate can change its rules.
It has a disreputable history; CNN calls it “a relic of Jim Crow.” (Read story here.) “Southern senators took advantage of the filibuster for years to block civil rights legislation — including anti-lynching bills,” CNN says.
But this is here and now. Proponents argue it’s a necessary safeguard to prevent “majority tyranny” by providing the minority faction in Congress with a check on the majority. But the Republican minority already has a large check on the Democratic majority by having an equal number of senators with 41.5 million fewer votes. When they had more senators with fewer votes, that was a filibuster in itself. So that check is in place; it simply falls short — by 1 vote — of being an absolute veto.
At issue is a bill, H.R. 1 — the voting rights bill already passed by the House — that would strengthen our democracy, not weaken it, by protecting the right to vote from the GOP’s strenuous efforts to deny that right to millions of America.
In the current context, the Senate filibuster isn’t a check on “majority tyranny” at all, it’s an instrument of minority tyranny, just as when racists used it to shield lynchings from the reach of federal law enforcement.