Bernie-mania hit Vatican City today with a crush of Italian media, cameras, boom microphones, shouting reporters and a ring of civilians, smartphones held aloft, chanting "Bernie, Bernie, Bernie!"

Sanders was not there to meet with Pope Francis, who is on the road himself visiting a refugee camp in Greece. The Democratic hopeful had accepted an invitation from the Pontifical Academy of Social Sciences to speak at a conference on social and economic justice.

Speaking to reporters at the Vatican, Sanders noted that he had a choice, given the timing of the event — stay in New York in advance of the state's big delegate-rich presidential primary vote, or head to Europe.

"I know it's taken me away from the campaign trail for a day," he said. "But when I received this invitation, it was so moving" that he felt compelled to come.

The Vermont senator boarded a charter flight — along with staff and his traveling press corps — after the Democratic presidential debate in Brooklyn and flew overnight to Rome, arriving early afternoon local time.

No surprise that Sanders' message in Italy was the same as it has been in speeches from Iowa and New Hampshire to Wisconsin and now New York state.

At a press conference, Sanders spoke of a world where "people are so much more concerned about their own billions than they are about our children and the future of our planet."

"We have to ingrain moral principles into our economy that serve more than those who are at the top," he said.

And while meeting Pope Francis was never on Sanders' schedule for this round-trip red-eye visit to the Vatican, the senator was quick to praise the pope's agenda and in the process make it clear that on these big economic issues, the two are kindred spirits.

"I have been enormously impressed by Pope Francis speaking out, and his visionary views about creating a moral economy, an economy that works for all people, not just the people on top," Sanders said.

The images of the warm greeting the candidate received at the Vatican, along with the swarms of cameras and reporters as he emerged from the conference, are certainly a positive for the Sanders campaign.

While there are many Catholic Democratic voters in New York, Pennsylvania and Maryland, which all hold primaries in the coming weeks, it's not clear whether Sanders' visit to Rome will hold much electoral impact. Still, the conference was on a subject Sanders has built his entire run for the White House around.

The downside may be the time spent away from New York just four days before the state's primary. There are rallies he could be holding, hands he could be shaking, and voters he could be inspiring as the clock ticks down. Polls show him trailing Clinton in the Empire State by double digits.

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