AP EXPLAINS: What is the Senate's 'nuclear option'?

WASHINGTON (AP) — President Donald Trump said Wednesday that Senate Majority Leader Mitch McConnell should "go nuclear" if necessary to approve his Supreme Court nominee, Judge Neil Gorsuch.

What does that mean?

It's a reference to the "nuclear option." That is the nickname for a potential move by Republicans to unilaterally change Senate rules so that Gorsuch's nomination could be approved with a simple majority in the 100-member Senate, instead of the 60 votes now required.

IT'S HAPPENED BEFORE

This procedural maneuver has recent precedent. In 2013, when Democrats were in the majority under the leadership of then-Sen. Harry Reid of Nevada, they pushed through a rules change lowering the vote threshold on all nominees except for the Supreme Court from 60 to a simple majority.

The Supreme Court was exempted at the time as part of a deal bringing along Democrats reluctant to change the rules. Some Democrats, including the current leader Chuck Schumer of New York, have voiced regret, since the changed rules are now allowing Trump to push his Cabinet picks through the Senate and Democrats can do little to stop him.

WHY IT WOULD BE EXPLOSIVE

Such a rules change on Supreme Court nominees would be a momentous change for the Senate, which traditionally operates via bipartisanship and consent from all senators. Some believe it could begin to unravel Senate traditions at a hyperpartisan moment in politics and perhaps end up in the complete elimination of the filibuster even for legislation, which would mean an entirely different Senate from the one that's existed for decades.

Senate experts note that the filibuster is not enshrined in the Constitution and filibustering nominees is a relatively recent phenomenon. Cloture — the procedural motion to end a filibuster — was attempted for the first time on a nominee in 1968 as President Lyndon Johnson tapped Abe Fortas as chief justice of the Supreme Court, according to the Congressional Research Service.

The cloture attempt failed and the nomination was withdrawn.

McConnell is an institutionalist who has made clear he does not favor invoking the nuclear option, but has not ruled it out for Gorsuch.

The Senate is currently split with 52 Republican seats and 48 controlled by the Democrats.