SCOTUS fight: Senate barrels toward 'nuclear' showdown over Gorsuch

The Senate is barreling toward a showdown that could alter how the body governs itself and have far-reaching implications for the nation's highest court.

The fight is over the confirmation of President Donald Trump's Supreme Court nominee Neil Gorsuch, but the nominee himself is perhaps more collateral damage than incendiary spark after a decade of Senate infighting that has bred a toxic atmosphere of mistrust and animosity. The high-stakes political battle waging around him could lead to a major change in Senate rules and pave the way for more overtly ideological nominees to the high court.

The Senate Judiciary Committee will vote Gorsuch's nomination out of committee Monday, likely along party lines. The next step is for the full Senate to consider his nomination, a process that could move the Senate into unprecedented territory.

Emboldened by their political bases, Senate Majority Leader Mitch McConnell and Senate Minority Leader Chuck Schumer are entering the week by standing firm.

"Neil Gorsuch will be confirmed this week. How that happens will really depend on what will happen with our Democratic friends," said McConnell on NBC's "Meet the Press" on Sunday.

Schumer and his fellow Democrats could block Gorsuch's nomination because they are requiring a 60-vote threshold for him to pass — also known as a filibuster. With only 52 Republicans, the GOP will have to find the support of eight Democrats. As of Sunday evening, only three Democrats said they'd oppose a filibuster, and just eight remained undecided.

Related: These Are the Democrats Voting Against Neil Gorsuch

Republicans are seemingly prepared to respond by changing the Senate rules to allow Supreme Court nominations to pass with a simple majority, a dramatic move known as the "nuclear option." Such a move would be the latest escalation in a long-running partisan battle over the judiciary and other presidential appointments in the upper chamber.

"You shouldn't change the rules. You should change the nominee," said Schumer, who predicted on "Meet the Press" that Gorsuch will not receive the support of 60 senators.

"It's a big deal," said Norm Orenstein, scholar at the center-right American Enterprise Institute. "You have a situation where you have rules and you have norms of behavior. The rules provide some significant check, but you still gotta operate with norms."

And while both Republicans and Democrats are aware of the calamity of the impending outcome, they also recognize that damage might be beyond repair after years of increased partisanship.

Republican Senator John McCain of Arizona has been engaged in conversations with some of his Republican and Democratic colleagues to stave off the worst-case scenario, but those haven't yet led to true negotiations.

Sen. Chris Coons (D-Del.) is one of the Democratic senators McCain has spoken to, but Coons said there is "not a lot of common ground" to work with.

"There is not a lot of trust between Republicans and Democrats in the Senate," Coons told NBC News.

Sen. Claire McCaskill, R-Missouri who is up for re-election in 2018 in a state that Trump won, announced her opposition to Gorsuch on Friday, and said she'd go a step further and support a filibuster against him. She admitted in a Medium post that her decision could have deep political ramifications in the future.

"I remain very worried about our polarized politics and what the future will bring, since I'm certain we will have a Senate rule change that will usher in more extreme judges in the future." McCaskill wrote.

Democrats forced a rules change in 2013 after Senate Republicans blocked most of President Barack Obama's judicial nominees and several cabinet positions. The "nuclear option" imposed then reduced the threshold for passage from 60 votes to 51 votes for all cabinet and judicial positions other than the Supreme Court, allowing Obama's nominees to pass. It's a decision that Schumer has said he laments.

But McConnell's refusal to even consider President Barack Obama's Supreme Court nominee Merrick Garland, not giving him a hearing or even holding meetings, inflamed tensions.

The Republican leader has cited election-year politics as the reason for that decision — and it is one that Democrats admit is playing into their considerations on Gorsuch, who would assume the seat that has sat vacant since Justice Antonin Scalia died more than a year ago.

"As I talk to Democrats, I think we are all outraged at how Merrick Garland was treated in the process and that got us to where we are today. As I talk to Republicans, they remind me of the 2013 changes in rules," Coons said. "And frankly there is a long list of back and forth, back and forth about we believe they badly mistreated Barack Obama's nominees and they believe that Barack Obama overreached and that we were oblivious or unconcerned about their issues to executive overreach."

Buoyed by their party's activists, Schumer and McConnell have little incentive to ratchet down the extremes. The Senate's mood is reflective of the mood in the country. In a recent NBC News/Survey Monkey poll released last week, 84 percent of Republicans want a vote on Gorsuch while only 31 percent of Democrats do. (However, most polls taken after Garland's nomination indicated that a majority of Americans wanted him to be confirmed.)

Liberal groups are urging the Senate Democrat's campaign arm, the DSCC, to challenge Senators Joe Manchin of West Virginia and Heidi Heitkamp of North Dakota because they have announced that they will support Gorsuch. Senator Joe Donnelly of Indiana is the third Democrat to announce his support for Gorsuch.

"I was deeply disappointed by the way the most recent Supreme Court nominee, Judge Garland, was treated by the Senate, but as Senator, I can only vote on the nominee that comes to the Senate floor," Donnelly said in a statement Sunday. "However, I believe that we should keep the current 60-vote threshold for Supreme Court nominees."

And on the right, the conservative Judicial Crisis Network, which has spent at least $10 million targeting senators over Gorsuch, put out a statement ahead of this week's vote.

"We will be on the front lines supporting him and his colleagues," Carrie Severino, chief counsel of the Judicial Crisis Network, said in a statement. "Chuck Schumer is engaged in a scorched-earth, first-ever partisan filibuster to try and block Judge Gorsuch."