VATICAN CITY — For a while, Senator Bernie Sanders’s Roman holiday seemed less than it was cracked up to be.

Immediately after his campaign announced that he would leave the United States for a “high-level meeting” at the Vatican, questions arose about the wisdom of the trip. The critical New York primary was just days away. One official of the Vatican’s Pontifical Academy of Social Sciences, which hosted the conference Mr. Sanders would attend, even suggested he had fished for the invitation.

Most critically, there seemed to be little chance that Mr. Sanders would meet the Vatican resident whose name he frequently invokes. Pope Francis, it turned out, would not be visiting the conference of the academy, an in-house think tank of the Vatican.

Politically, a trip to Rome without a meeting with Francis would have been a blunder, Costas Panagopoulos, a political science professor at Fordham University who is teaching at Yale, had said on Friday. “The point is to make sure you are going to get an audience with the pope,” he said. “Anything short of an actual visit will probably be a mistake.”