President Obama’s nomination of a judicial moderate to fill the Supreme Court vacancy created by the death of Justice Antonin Scalia leaves the Republican leaders in the Senate with no justification to shirk their constitutional role to either deny or confirm the selection.

In fact, Republicans should be motivated to act on the appointment. It’s the Democratic Party’s progressive wing that should feel queasy about the choice.

In calling their bluff by nominating appeals court judge Merrick Garland, Obama has offered Republicans a potential justice who may prove far more palatable than any candidate they get after the November presidential election. As things stand, Republicans are on a course to nominate as their candidate Donald Trump, who has alienated entire swaths of the electorate with his divisive rhetoric.

GOP leaders are hoping to derail the Trump nomination — a window that is rapidly closing after Trump's strong showing Tuesday — because they recognize his candidacy would lead to the election of the likely Democratic nominee, Hillary Clinton, and in the process Republicans could also lose their grip on the Senate.

Do Republicans truly want to persist in their refusal to act on any Supreme Court nomination? Do they really want to wait and let Clinton, who would not be motivated to settle for a moderate, pick the next justice?

At this point, many Democrats would probably just as soon wait, given how the presidential election is shaping up. Continuing Senate delay would give the Democrats an issue to use against the Republicans in the election and the opportunity to fill the vacancy after the election.

In other words, continued stalling would be politically foolish for the Republicans.

So if Senate Republicans do not want to act because it is their constitutional responsibility, perhaps they can be motivated by political pragmatism. This may be the calculation Obama is making in hoping to see his last appointee to the high court confirmed before he leaves office.

Consider the interview Sen. Orrin Hatch, R-Utah, had with the conservative news site Newsmax just a few days ago.

“The President told me several times he’s going to name a moderate, but I don’t believe him," Hatch said. “(Obama) could easily name Merrick Garland, who is a fine man. He probably won’t do that because this appointment is about the election. So I’m pretty sure he’ll name someone the (liberal base) wants.”

Well, believe him, senator.

At age 63, Garland would not likely serve three decades as Scalia did, eliminating one Republican fear of an Obama appointee having excessive longevity. The chief judge for the U.S. Court of Appeals of the District of Columbia Circuit, in 2003 Garland took the conservative side in joining in a decision that effectively prohibited Guantanamo Bay detainees from turning to civilian courts for legal relief of their grievances. The Supreme Court reversed the decision.

Garland, a former federal prosecutor, also has a conservative record on appeals by criminal defendants. In 2010, when Garland’s name surfaced as a possible Supreme Court nominee, court observer Tom Goldstein noted on his SCOTUSBlog, “to the extent that the president’s goal is to select a nominee who will articulate a broad progressive vision for the law, Judge Garland would be a very unlikely candidate to take up that role.”

In his comments Wednesday after the president named Garland as his nominee, the judge sounded what should be music to conservative ears, vowing to “follow the law, not make it.”

Which is not to say Garland would be the pick of a Republican president. He likely will side with the progressive wing of the court much of the time. It is to say, however, that this pick is about the best Republicans could expect. This explains why in 1997, when confirmed as an appellate judge, Garland received majority backing from both parties, including from seven Republicans still serving in the Senate.

He is eminently qualified, having led the court considered second only to the Supreme Court in importance. He graduated from Harvard Law School with high honors. He clerked for Supreme Court justices William Brennan Jr. and Henry J. Friendly, both nominees of Republican President Dwight D. Eisenhower. As a prosecutor, he led the investigations and prosecution into the Oklahoma City bombing.

Republicans have no excuse for not acting on this nomination. In fact, they have every reason to act and should do so expeditiously.