WASHINGTON — (CNN) Neil Gorsuch’s nomination to the Supreme Court faces a dramatic week as senators prepare to cast key votes that could splinter the chamber and lead to a divisive rule change imposed by Republicans to ensure they can confirm the judge by Friday.

With only three Democrats saying they will back the 49-year-old Coloradan, it’s increasingly likely Gorsuch can’t get the 60 votes he needs to overcome a Democratic filibuster. If that holds — as top senators and aides in both parties generally expect — Republicans promise to use the “nuclear option,” to change Senate rules over the objection of Democrats so the GOP can advance Gorsuch on a party line vote.

There have been informal talks between bipartisan senators to head off the crisis but to this point no deal seems near. Many senators are worried that the if Republicans weaken the filibuster for Supreme Court nominees, in the same way Democrats did for all other presidential appointments in 2013, the chamber would be on a slippery slope and the filibuster for legislation could someday be diminished too.

They believe that would make the Senate even more partisan and less able to respond to the nation’s needs.

Democrats argue Gorsuch is outside of the judicial mainstream and was selected off a campaign-season list compiled by President Donald Trump to satisfy the far-right wing of the Republican Party. They want to block Gorsuch and force Trump to pick another nominee who Democrats could back.

“If Judge Gorsuch fails to garner 60 votes, the answer isn’t to irrevocably change the rules of the Senate; the answer is to change the nominee,” Senate Minority Leader Chuck Schumer, D-New York, said last week.

Democrats also are still fuming the Republicans refused to act on the nomination of Judge Merrick Garland, who former President Barack Obama picked more than a year ago for this same vacancy.

Republicans counter that Gorsuch is superbly qualified with backing from legal scholars across the political spectrum. They believe Democrats are politically motivated and will never confirm a high court nominee picked by Trump, which justifies their decision to use the nuclear option.

“We will confirm Judge Gorsuch this week,” Senate Majority Leader Mitch McConnell said on “Fox News Sunday.”

“The way in which that occurs is in the hands of the Democratic minority,” the Kentucky Republican added. “I think during the course of the week we will find out exactly how this will end, but it will end with his confirmation.”

Monday: Judiciary Committee votes

The action begins Monday at 10 a.m. when the Senate Judiciary Committee debates and votes to send Gorsuch’s nomination to the full Senate. A series of speeches — and probably testy debate — is expected from senators before roll call vote occurs.

Gorsuch is expected to clear the committee likely on a party-line vote, which Republicans control 11-9.

Most Democrats on the committee have already announced they oppose Gorsuch and will vote to filibuster him. But the committee’s top Democrat, Sen. Dianne Feinstein of California, hasn’t said what she will do although she’s talked about her deep concerns with some of his decisions on the 10th Circuit Court of Appeals, where he serves now. Sen. Patrick Leahy, D-Vermont, and Sen. Chris Coons, D-Delaware, have not said if they will filibuster Gorsuch.

Meanwhile, Sen. Joe Donnelly announced on Sunday that he will support Gorsuch’s nomination.

“After meeting with Judge Gorsuch, conducting a thorough review of his record, and closely following his hearing before the Senate Judiciary Committee, I believe that he is a qualified jurist who will base his decisions on his understanding of the law and is well-respected among his peers,” the Indiana Democrat said in a statement.

Democratic Sens. Heidi Heitkamp of North Dakota and Joe Manchin of West Virginia also have said they will support Gorsuch’s nomination.

Thursday: The filibuster showdown

On Tuesday, McConnell is expected to move to end the floor debate on Gorsuch setting up a critical vote Thursday morning to break the Democratic filibuster. For this vote, Republicans would need the backing of eight Democrats to get the 60 votes required to end the filibuster.

If Republicans don’t prevail, they will move to the nuclear option by voting on a motion to lower the number of votes needed to break a filibuster of a Supreme Court nominee from 60 to 51.

It is not assured McConnell can get the backing of his full conference for the nuclear option, although GOP leaders have sounded confident in their predictions. Some Republicans, like Susan Collins of Maine and Bob Corker of Tennessee, haven’t said what they will do. Because of this uncertainty, Vice President Mike Pence will be prepared to break a tie.

If the nuclear option is successful, Republicans would revote to break the filibuster, this time needing just 51 votes to do that.

Senate rules then allow for 30 hours of additional debate, setting up a final confirmation vote for Gorsuch Friday evening.

Gorsuch only needs a majority vote of those senators present and voting to be confirmed. So, 51 votes if all 100 senators are there voting.

He could then be sworn-in right away.

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