When former Senate Majority Leader Harry Reid invoked the nuclear option in 2013 — and changed the Senate rules so it would take only a bare majority of senators to confirm all nominees except Supreme Court picks — Republicans were furious. They called Reid's move foolhardy, pointing out that one day Democrats would suffer the consequences of the rules change when they end up in the Senate minority with a Republican in the White House.

That day has arrived. And now Republicans potentially have the power to further change the rules so the minority can't even block a Supreme Court nominee.

However, it takes 51 votes in the Senate to employ the nuclear option. And Republicans may not have the votes. Already one Republican — Susan Collins of Maine — says don't count on her vote.

"I am not a proponent of changing the rules of the Senate," said Collins on Monday evening. "I hope that common sense will prevail and that we will have a normal process for considering this nominee."

Vice President Pence could supply the 51st vote for Republicans to invoke the nuclear option. But without Collins on board, Republicans can lose only one more vote.

And Joe Mancian of WV has said he will not filibuster the nomination.