Not long ago, whether to confirm a Supreme Court nominee was not a predictably party-line affair, with a handful or fewer of defectors. In 2005, Chief Justice John G. Roberts Jr. was confirmed with 78 votes, and Democratic senators split equally on the nomination, 22 in favor and 22 against.

That lopsided tally - earlier confirmations were, for the most part, more lopsided - is now a quaint artifact of a less polarized era.

The Senate finds itself now on the verge of a dangerous new reality, in which a Senate controlled by the party opposing the president might simply refuse to confirm a nominee, period.

A tradition of deference to presidential prerogatives — of believing that elections have consequences, as Sen. Lindsey O. Graham (R-S.C.) liked to say in one of his earlier incarnations — is over. If the Senate majority is big and unified enough, it will defy the president.

Just wait and see. Republican senators were willing to caricature Ketanji Brown Jackson’s record in search of any excuse to vote against her — even though her addition to the court won’t affect its ideological balance. Imagine what would happen if a Republican appointee were to leave the court during a Democratic presidency. Actually, no imagination needed. Consider what the Senate did — or didn’t do — when Merrick Garland was nominated in 2016 to replace the late Antonin Scalia.

We could endlessly debate how things degenerated to this point: Republicans point to the Bork hearings, the Thomas hearings, the Gorsuch filibuster and the Kavanaugh hearings; Democrats bemoan the Garland blockade and the hurried Barrett confirmation. Neither side has clean hands.

The result is a fiercely partisan process that demeans the Senate and politicizes the court, rendering it a creature of political will and power. At this stage, there is no incentive for either party to back down from this maximalism.

Time was (starting with Robert H. Bork), the Senate debated whether a nominee was in or outside the judicial mainstream. That assessment was in the eye of the beholder, of course, but at least it was a nod at deliberation.

That is so 1987. Judicial philosophy is now aligned with political party as never before in the court’s history. So it is no surprise to witness the same phenomenon — the raw exercise of power overtaking normal processes — unfolding on the court itself. Norms are shredded in both branches.

One vivid manifestation involves the conservative majority’s use of the emergency docket — what’s called, in more sinister-sounding terms, the shadow docket.

The court’s work is supposed to be conducted after full written briefing and oral argument and justified by written opinions. It has rules, or is supposed to, about when to intervene to referee disputes before they get to that stage, and, of course, that needs to happen sometimes.

But increasingly, the court is using its emergency powers to step into disputes on the side that the majority favors — outside of the normal procedures and without written explanation.

Why? Because it can.

Thus, the week of Jackson’s confirmation saw five conservative justices — over the dissent of three liberals and the chief justice — intervening in a case still pending before a federal appeals court.

Five conservative justices voted to reinstate a Trump-era clean-water rule that restricted states’ ability to block potentially polluting projects.

The three remaining liberal justices — joined, notably, by Chief Justice Roberts — dissented, complaining that the court was misusing its emergency powers by reviving the rule without the proof that was necessary to avoid “irreparable harm,” as the court’s precedents require.

“That renders the Court’s emergency docket not for emergencies at all,” wrote Justice Elena Kagan.

This might sound mild, but process matters at the Supreme Court, and while Roberts had voted with the liberals before in such cases, this was the first time he had joined a dissent criticizing the misuse of the shadow docket.

Maybe the district court judge in the case made a mistake by going further than the Biden administration had asked in vacating the Trump-era regulation, not simply returning the matter to the Environmental Protection Agency while it worked on a new version of the rule.

That’s not the point. The point is that courts have rules about when to grant emergency relief — and the test isn’t just whether the lower court got it wrong. An appeals court is reviewing the district judge’s decision and, applying those rules, declined to stop it from taking effect. As Kagan explained in her dissent, “This Court may stay a decision under review in a court of appeals ‘only in extraordinary circumstances’ and ‘upon the weightiest considerations.’ ”

No emergency justified the Supreme Court interfering here. It just had the votes to act anyway.

When norms give way to partisanship and ideology, when applying impartial rules yields to obtaining results by any means, institutional legitimacy erodes. The immediate gain is understandably tempting. The institutional damage might not be immediately evident, but it is as undeniable as it will be difficult to repair.