Jim Geraghty of National Review Online is still waiting to learn Republican presidential candidate Donald Trump’s preferences for potential Supreme Court justices.

Back on March 21, Donald Trump, sensing there was some conservative anxiety about whom he would nominate to the Supreme Court, promise to compile and release a list of five to ten “great conservative judges” with “great intellects.”

“I will guarantee that those are going to be the first judges that I put up for nomination if I win,” Trump said. “And that should solve that problem.”

It’s mid-May now, Senate Republicans are holding the line against hearings or a confirmation vote on President Obama’s nominee, Merrick Garland, and there remains no sign that a list of potential Trump nominees is forthcoming.

Trump’s handling of the Supreme Court question is worrisome on three fronts.

First, there is the simple failure to deliver on a public promise. It’s been almost two months since he offered to produce his list of potential nominees, and there’s still no sign of it. If experience tells us anything, it’s that the list may never come. He’s made an entire campaign out of lying, flip-flopping, and even adopting contradictory positions simultaneously. Everything that comes out of his mouth is, as he’s so fond of putting it, “negotiable,” and there’s no reason to believe the promised Supreme Court shortlist is an exception.

Second, he gives little indication he’s spent more than a few minutes thinking about who would make a good pick for the Court, or about the role of the judiciary in our government. …

… Third, there’s little sign that Trump or anyone around him grasps how important and consequential the issue of judicial appointees is, or how much good it would do him to reassure Republicans who aren’t jumping on board the bandwagon. If there were a way to be absolutely certain that Trump would appoint two, three, or four Antonin Scalia clones during his presidency, a lot of Trump-skeptic conservatives might immediately see one giant reason to vote for him. If nothing else, they could rest easy knowing that the Second Amendment wouldn’t be effectively nullified or curtailed, that Citizens United would remain the law of the land, that voter-ID laws would be upheld, and that pro-lifers could continue to make progress in the courts.