Washington (CNN) The Supreme Court wars escalated this week when Democrats signaled they are ready to fight for the seat they believe should have gone to Merrick Garland, and already the prospect of the nuclear option is being discussed.

"Let's see who they nominate," Senate Minority Leader Chuck Schumer said Wednesday to reporters. "If they're in the mainstream we'll give them a very careful look. If they're out of the mainstream we'll oppose them tooth and nail."

And asked the night before by MSNBC's Rachel Maddow if he would consider trying to keep the seat vacant -- leaving the court with only eight justices -- Schumer said, "Absolutely."

"We are not going to make it easy for them to pick a Supreme Court justice," he said.

Senate Majority Leader Mitch McConnell responded immediately.

"The American people simply will not tolerate" Democrats blocking a Supreme Court nominee, he told reporters.

It is unclear when President-elect Donald Trump will nominate someone to fill the vacant seat on the bench.

Ratcheting up the debate could impact the type of person Trump selects. He has a list of 21 potential choices unveiled last year meant to appeal to conservatives. He has options. He could look for alternatives not on the list, dig deep on the list to find someone who might garner less controversy, or go big by naming Judge William Pryor — a conservative favorite who also has attracted the most opposition from liberals.

Others on the list include Judge Diane Sykes of the 7th Court of Appeals, Judge Thomas Hardiman from the 3rd Circuit and Judge Steve Colloton from the 8th Circuit.

A Pryor nomination would be considered the least "mainstream" name on the list for liberals and could possibly force Republicans to push for a rules change and do away with the filibuster that is in place for the Supreme Court seat. Changing the rules is a delicate subject. Old Guard Republicans might push back. In 2013 when then Majority leader Harry Reid led the charge to get rid of the filibuster for lower court nominees, Sen. John McCain took to the floor.

"We are approaching a slippery slope that will destroy the very unique aspect of this institution called the US Senate," he said.

Of course it was Democrats who opened the door to a rules change when they got rid of the filibuster for the lower courts, something Schumer says he regrets.

"Wish it hadn't happened," Schumer told CNN's Dana Bash this week.

The argument could be made that Republicans would never have taken that first step. Secondly, there is a good chance that Trump will have more than one chance to name a Supreme Court Justice given that three justices are in their late 70's and early 80's. That seat could be the big fight as it would most likely move the court further to the conservative side. The argument: since that seat might prompt a rules change why not do it now?

Richard Arenberg, a former staff member for three Democratic senators and co-author "Defending the Filibuster: The Soul of the Senate" wrote this week in the New York Times that the Republicans shouldn't weaken the filibuster.

"The Senate has historically been the one place in our government where legislative minorities are protected, with rules to check overzealous majorities," Arenberg wrote. He said Republicans have other options such as using public opinion to force votes, requiring debate around the clock and focusing on endangered Democratic senators who must run for re-election in 2018 in states that Trump won.

The irony of the debate is not lost on anyone.

After Schumer suggested he might work to hold the seat open, conservative Ed Whelan tweeted "seems like just yesterday that Left insisted that having only eight justices is a constitutional crisis."

And when McConnell said that the American people would not allow the seat to remain open Jason Steed, an appellate lawyer, posted on twitter a fake picture of a head exploding referencing the fact that it was the Republicans just a few months ago who held the seat open.

The Heritage Foundation's John Malcolm has praised Trump's list of 21 and sees a big difference now that the election is over. After Justice Antonin Scalia's death, McConnell said the seat should not be filled so close to the election so that the American people could choose.

Malcolm told the Daily Signal that voters were faced with the concept of a liberal majority on the court.

"The voters, however, rejected this vision of where the court ought to go," Malcolm told the Daily Signal.

Elizabeth Wydra of the progressive Constitutional Accountability Center sees things differently.

"Given that most Americans support Roe v Wade, oppose flooding the political system with special interest cash, and believe in the values of equality and inclusion expressed in the Constitution, there is no reason to think they would support a Supreme Court nominee who would promote an extreme conservative agenda from the bench," she said.