The political wrangling over President Donald Trump’s choice for the US Supreme Court has set up what could turn out to be an unprecedented battle in the Senate. Democrats on Monday were poised to block Judge Neil Gorsuch, depriving him of the 60-vote threshold needed to avoid a filibuster.

Senate Majority Leader Mitch McConnell was expected to invoke the so-called nuclear option, setting up a likely vote to change the rules to eliminate the filibuster for Supreme Court nominations in order to get Gorsuch confirmed.

Rep. Adam Schiff of California said of that option on Monday: “When McConnell deprived President Obama of a vote on Garland, it was a nuclear option. The rest is fallout.”

Obama nominated Judge Merrick Garland in March last year. Republicans refused to hold congressional hearings, despite Obama having more than 10 months left in his second term. The move was roundly criticised, but Republicans argued the American public should have a say based on whom they would vote for in last year’s presidential election.

Senate Democrats have vowed to try to stop Gorsuch’s confirmation, citing concerns about his history on the judiciary and the multiple investigations into potential ties between the Trump administration and Russia.

The nuclear option has been invoked in Congress before. Former Senate Majority Leader Harry Reid employed it to help get Obama’s judicial and executive nominees confirmed.

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