Three Church leaders did not specifically name the politician.
However, the President of the US Conference of Catholic Bishops (USCCB), Joseph Kurtz, and USCCB chairmen, Bishop Richard Malone and Archbishop Thomas Wenski wrote that "When a prominent Catholic politician publicly and voluntarily officiates at a ceremony to solemnise the relationship of two people of the same-sex, confusion arises regarding Catholic teaching on marriage and the corresponding moral obligations of Catholics."
The Tablet has reported that the wedding of two long-term White House aides took place at the Vice President's official residence on the grounds.
Joe Biden officiated the ceremony.
The bishops continued: "Questions revolving around marriage and human sexuality are deeply felt in our homes and communities.
"We join with our Holy Father Pope Francis in affirming the inviolable dignity of all people and the Church's important role in accompanying all those in need.
"In doing so, we also stand with Pope Francis in preserving the dignity and meaning of marriage as the union of a man and a woman."
They said Catholic politicians need to "recognise their grave responsibility in society to support laws shaped by these fundamental human values."
Speaking in 2012, Joe Biden said he was comfortable with same-sex couples marrying and stressed that he thought gay, lesbian and straight couples all deserved the same rights.
In June 2015, the US Supreme Court declared same-sex marriage legal in the USA.
