President Trump and his allies have excoriated Mitch McConnell, the Republican leader in the Senate, for his failure to pass important legislation. McConnell is responding, in part, by stepping up his efforts to transform the federal judiciary. If he succeeds, Democrats will lose their only tool to block even the most reactionary judges from winning lifetime appointments.

Of course, McConnell already has a singular success to boast about to conservatives who are frustrated with his rule. After blocking President Obama’s appointment of Merrick Garland to replace Antonin Scalia on the Supreme Court, McConnell shepherded Trump’s choice of Neil Gorsuch to confirmation, earlier this year. But this victory didn’t quiet McConnell’s critics on the right, so the Majority Leader is offering them a free hand for choosing the rest of the federal judiciary as well. Because of McConnell’s stonewalling of not only Garland but also Obama’s lower-court nominees, Trump has dozens of judicial vacancies to fill.

McConnell’s vehicle for further marginalizing Senate Democrats involves an obscure tradition known as the blue slip. The President nominates all federal judges, but for decades the home-state senators for all nominees have been asked for their approval of the choices. If the senators agree, they submit a form (on blue paper) that ratifies the choice. If they do not approve of the nominee, they do not return the so-called blue slip—and the Judiciary Committee does not move the nominee forward to a hearing and a vote.

The blue-slip rule does not have the force of law; it’s simply a custom that has been honored over time. Notably, when Patrick Leahy, the Vermont Democrat, was the chairman of the Judiciary Committee, during the Obama Administration, he followed the blue-slip rule in states where there were Republican senators. If these senators did not return their blue slips—and many did not, especially in Texas and other Southern states—Leahy buried the President’s nominees. In truth, the blue slip is a rather dubious tradition, one that has historically given senators a little-deserved veto power over a President’s choice. But, because Senate Republicans exercised this power over Obama’s nominees, it’s only fair—indeed, it’s obligatory—that Senate Democrats have equal say when it comes to Trump’s.

The current showdown began in September, when Al Franken, the Minnesota Democrat, refused to return a blue slip for Trump’s nomination of David Stras, a Justice on the Minnesota Supreme Court, to serve on the Eighth Circuit Court of Appeals. Rather than honor the blue-slip tradition, McConnell said that he would ignore it and deprive Senate Democrats of the veto power that Republicans enjoyed during the Obama years. As McConnell told The Weekly Standard, the Republican majority in the Senate will treat blue slips “as simply notification of how you’re going to vote, not as an opportunity to blackball.”

In truth, it’s not entirely clear how a showdown over blue slips will turn out. Chuck Grassley, the Iowa Republican, is now the chairman of the Judiciary Committee, and he’s both turf-conscious and prickly about defending the traditions of the Senate. Grassley has indicated some misgivings about honoring McConnell’s blue-slip diktat. Still, it seems clear that McConnell will quicken the pace of confirmations, by whatever means necessary, and hasten the transformation of the federal judiciary.

To a great extent, Trump has outsourced judicial selections to the Federalist Society, the national organization for conservative lawyers. The Senate has already confirmed four Court of Appeals judges and two for the district courts, but a torrent of confirmations is likely in the next few months. There are fourteen nominations pending to the Courts of Appeals, and thirty-seven to the district courts, and, so far, there has been no organized opposition to any of them. A handful, like Stras, might be stopped if Republicans honor blue slips, but that possibility appears to be fading. Thanks to the so-called nuclear option, which Harry Reid and the Democrats invoked in 2013, none of these nominations can be filibustered; they can all be confirmed by a simple majority, and there are fifty-two Republicans in the Senate. Three Republicans (John McCain, Lisa Murkowski, and Susan Collins) took the bold step of sinking the Republican plan to overturn the Affordable Care Act, but there has been no sign of a similar rebellion against any of the President’s judicial nominees—and, of course, it would take three defections to stop any of them. Accordingly, the prospect of doing so seems highly remote.

And who are these nominees? For the most part, the circuit-court nominees have impeccable formal qualifications—distinguished academic records, judicial clerkships, impressive legal careers. They are almost all young by judicial standards, many in their early or mid-forties. And they are deeply conservative—with records that suggest hostility to voting rights, gay rights, and constitutional protections for a woman’s right to choose. Their clerkships are with conservative judges, like Scalia and Clarence Thomas, and they have been chosen to reflect the judicial philosophy espoused by those Justices. These are the kinds of judges whom Trump promised during his campaign, and these are the judges whom McConnell has vowed to deliver—and it looks like he’s going to get them, sooner rather than later.