Joe Biden has been back in Washington for six days, and already he has attended Catholic Mass twice.
His first visit was to St Matthew's Cathedral in downtown Washington on the morning of his inauguration. Then, on the first Sunday of his presidency, he took in morning services at Holy Trinity Church, in the Georgetown neighbourhood of northwest DC.
The Jesuit-affiliated Holy Trinity is the same church to which John F Kennedy, the nation's first Catholic president, belonged. It's just a few blocks from Georgetown University, the nation's oldest Catholic college.
Public displays of religiosity are not uncommon among US presidents, but Biden appears poised to be the first president since Bill Clinton, who was a congregant at the Foundry Methodist Church, to regularly attend church services while in office.
George W Bush, a born-again Christian, did so infrequently - in part because of security concerns after the 11 September attacks. Barack Obama was similarly scarce, while Donald Trump preferred to spend his Sunday mornings at his private golf club in Virginia.
Jimmy Carter in the 1970s set the standard among modern presidents, as he was both a member and Sunday school teacher at First Baptist Church of DC. (The now 96-year-old ex-president continued to teach at a church in Plains, Georgia, until the coronavirus pandemic curtailed services last year.)
Joe Biden has been open about his Catholic faith, having referred to it frequently over the course of his public life. He quoted St Augustine in his inaugural address and Ecclesiastes 3 in his presidential victory speech.
Biden's views on some hot-button social policies have already led to clashes with the Catholic hierarchy in the US, however.
Archbishop Jose H Gomez, president of the US Conference of Catholic Bishops, released a statement the morning of Biden's inauguration noting the historic nature of his election, but also offering words of warning.
"Our new president has pledged to pursue certain policies that would advance moral evils and threaten human life and dignity, most seriously in the areas of abortion, contraception, marriage and gender," he wrote. "Of deep concern is the liberty of the church and the freedom of believers to live according to their consciences."
Such views are far from universal in the Catholic Church, though - and were reportedly poorly received by the Vatican itself.
Following Biden's inauguration, Pope Francis sent the new president a message of congratulations that stood in sharp contrast to the Los Angeles archbishop's words.
"At a time when the grave crises facing our human family call for farsighted and united responses, I pray that your decisions will be guided by a concern for building a society marked by authentic justice and freedom, together with unfailing respect for the rights and dignity of every person, especially the poor, the vulnerable and those who have no voice," he wrote.
In 2013, Pope Francis wrote that the church had become "obsessed" with "issues related to abortion, gay marriage, and the use of contraceptive methods".
The Jesuit pope and the new US president may end up forging an alliance of sorts, attempting to direct American Catholicism away from the conservative social politics of recent years - and toward a ministry focused on issues like racial and economic justice and the environment.
They could accomplish a political and religious realignment in the country or provoke an increasingly heated conflict.
"Trump clearly helped create the atmosphere that emboldened and enabled right-wing Catholics not only to mount their campaign against Francis, but also to attack Biden's Catholicism," writes Massimo Faggioli, a professor of theology and religious studies at Villanova University.
"Attempts at schism may have failed, but it's hard to believe that Trump's departure will quiet these efforts, at least as long as Francis is pope and Biden is in the White House."