[NEW YORK] A senior Vatican official accused Democratic presidential candidate Bernie Sanders of showing a "monumental discourtesy" in his lobbying for an invitation to a church- sponsored conference on economic and environmental issues for political purposes.
Mr Sanders, whose foreign policy experience is under attack by rival Hillary Clinton, on Friday said he was "very excited" about being invited to the meeting hosted by a pontifical academy.
It will put him at the seat of the Roman Catholic Church just four days before the New York primary.
The head of the academy said Friday that Mr Sanders sought the invitation and that put an inappropriate political cast on the gathering.
"Mr Sanders made the first move, for the obvious reasons," Margaret Archer, president of the Pontifical Academy of Social Sciences, which is hosting the conference Mr Sanders will attend, said in a telephone interview.
"I think in a sense he may be going for the Catholic vote but this is not the Catholic vote and he should remember that and act accordingly - not that he will."
Mr Sanders's travel to the Vatican following a debate with Clinton and just before the primary potentially injects into the Democratic nominating contest the agenda of Pope Francis, one of the most popular world leaders whose papacy is especially admired by the political progressives who play an outsized role in Democratic primaries.
Ms Archer's response plays into criticism by Mrs Clinton of Mr Sanders's inexperience in diplomacy and dealing with foreign institutions, a central role of the US president.
Pope Francis has raised the Catholic church's emphasis on issues of poverty, environmental stewardship and aid to refugees.
The Pope already has played a role in this year's election through criticism of anti-immigrant policies embraced by Republican candidates.
Mr Sanders told reporters in New York on Friday that he is "very excited about this invitation from the Vatican to participate in a major conference dealing with how we can inject morality into today's economy."
Mr Sanders, who's made economic disparities the centerpiece of his campaign, said Pope Francis "has been an extraordinary leader in making the world conscious of the levels of income and wealth inequality that exist on our planet."
Presidential candidates including Democrat Barack Obama in 2008 and Republican Mitt Romney in 2012 made tours of foreign capitals to respond to criticism of inexperience though in both cases they traveled to multiple countries and waited until after they had clinched their party's nominations.
The invitation was announced Friday by Mr Sanders and by the Pontifical Academy of Social Sciences, which is hosting the conference.
It was made public on the same day Pope Francis released a document calling for the church to be more welcoming and less judgmental and signaling a path for divorced and remarried Catholics to receive communion.
The conference Mr Sanders will attend marks the 25th anniversary of an encyclical by Pope John Paul II that criticized excesses of unfettered capitalism.
Foreign leaders including Ecuadorean President Rafael Correa and Bolivian President Evo Morales also will attend the conference, as will international development economist Jeffrey Sachs, according to a statement released by the pontifical academy.
Pope Francis injected himself into the US presidential campaign in February when he responded to a journalist's question about Republican Donald Trump's proposal to build a wall along the US southern border to prevent immigrants from crossing illegally.
"A person who thinks only about building walls, wherever they may be, and not building bridges, is not Christian," the Pope responded. He demurred when asked if Catholics should vote for Trump.
"As far as what you said about whether I would advise to vote or not to vote, I am not going to get involved in that. I say only that this man is not Christian if he has said things like that," Pope Francis responded.