Trump announced his Supreme Court nominee last night. Resistance emerged almost immediately.

What’s going on?

Early last year, Supreme Court Justice Antonin Scalia died. Since then, the Supreme Court has consisted of 8 justices. President Obama nominated Merrick Garland, but Republicans refused to give his nominee a hearing at all, instead putting all their hopes on winning the November election (which they did) so they can put forth their own choice (which they have).

Democrats–a minority in the Senate, but with enough seats to keep Republicans from a 60-seat supermajority–have promised to filibuster Trump’s pick, Neil Gorsuch. Republicans would require 60 votes to break a filibuster, or they would have to invoke the “nuclear option,” which is a procedural rule by which a nominee can be approved by a simple majority vote. Using the “nuclear option” would be an unprecedented move for a Supreme Court pick.

Why is it important?

First, Obama presented a highly-qualified nominee for the Court in Merrick Garland. It is the President’s right, under the Constitution, to appoint Supreme Court justices, and it is the responsibility of the Senate to confirm or reject such nominees. The Republican Senate under Obama refused to allow this for Garland. Now, they want get Trump’s pick confirmed.

Democrats intend to block this for fairly obvious reasons: payback for the obstruction against Garland, and as a general resistance move against Trump and Congressional Republicans.

Republicans might claim that Democrats are causing a Constitutional crisis, but the fact is that Republicans crossed this bridge first. President Trump did not win with a mandate–most Americans do not approve of his agenda. And his Supreme Court pick is in the mold of Scalia: a staunch conservative who will uphold a conservative agenda, giving Democrats no real reason to support his appointment.

The balance of the Supreme Court is deeply important to the legal, political, and social environment in this country. Whether people’s rights are respected or abridged, and whether meaningful legislation is upheld, often comes down to one vote on the Supreme Court.

What can I do?

Contact your Senators. Same drill as yesterday, really: encourage Democrats to filibuster and block Gorsuch from the Court and support the ones who’ve already promised to do so; encourage Republicans not to support him (as much of a losing battle as this may be).