By David Lawder
WASHINGTON (Reuters) - House Speaker John Boehner on Thursday invited Pope Francis to address a joint session of Congress - an unprecedented event - during an expected visit to the United States next year.
Republicans and Democrats on Capitol Hill have quickly sought to invoke the popular pontiff's devotion to the poor.
Francis, who on Thursday marked the first anniversary of his election as the leader of the world's 1.2 billion Catholics, is widely expected to travel to Philadelphia in September 2015 to attend the World Meeting of Families.
Mayors of several other U.S. cities have invited him to visit and Boehner moved to secure a spot on the pope's itinerary in a letter to sent to the pontiff on Thursday.
"It is with reverence and admiration that I have invited Pope Francis, as head of state of the Holy See and the first pope to hail from the Americas, to address a joint meeting of the United States Congress," Boehner said in a statement.
While Pope John Paul II visited Washington in 1979 and Pope Benedict XVI visited the U.S. capital in 2008, the U.S. Senate Historian's office said it has no record of a pontiff ever addressing Congress.
"Pope Francis has inspired millions of Americans with his pastoral manner and servant leadership, challenging all people to lead lives of mercy, forgiveness, solidarity, and humble service," added Boehner, the highest-ranking U.S. elected official who is Catholic.
But the Ohio Republican also used the occasion to reiterate Republicans' views that increased government spending and welfare programs are not the way to meet Americans' responsibility to care for the poor and the most vulnerable.
He said Americans "have embraced Pope Francis' reminder that we cannot meet our responsibility to the poor with a welfare mentality based on business calculations. We can meet it only with personal charity on the one hand and sound, inclusive policies on the other."
Boehner and Republican House Budget Committee Chairman Paul Ryan, also a Catholic, have come under fire in recent years from U.S. Catholic bishops over their spartan budgets, which have proposed major cuts to programs aimed at helping the poor, in part to reduce tax rates.
Ryan and Boehner have argued that federal handouts and big government programs violate the Catholic principle of "subsidiarity," which suggests that human affairs are best handled at the lowest level, closest to those affected. Instead, they advocate that the action of individuals, charities and private institutions and firms should take precedence in caring for the poor.
Previous Ryan budgets backed by Boehner have prompted sharp criticism from U.S. Catholic bishops, who have argued that their cuts would hurt the poor, elderly and sick, conflicting with Church teachings to aid the vulnerable.
Francis, a Jesuit who has taken a vow of poverty, last November called unfettered capitalism as a "new tyranny," and criticized "trickle-down" economic theory, which is favored by many U.S. Republicans.
In his first major document authored as pope, he argued that growth encouraged by unfettered financial markets will not result in greater social justice and inclusiveness.
In the same document, the pontiff also lamented growing income inequality around the world, a cause that U.S. Democrats have taken up as they seek to win back more seats in November congressional elections.
"This imbalance is the result of ideologies which defend the absolute autonomy of the marketplace and financial speculation," Francis wrote.
House Democratic Leader Nancy Pelosi, who is also Catholic, welcomed Boehner's invitation to the pontiff.
"Pope Francis has lived his values and upheld his promise to be a moral force, to protect the poor and the needy, to serve as a champion of the less fortunate, and to promote love and understanding among faiths and nations," Pelosi said.
President Barack Obama, who is advocating an increase in the U.S. minimum wage, among other social policies, is scheduled to meet with the pope at the Vatican on March 27 during a trip to Europe.
(Reporting by David Lawder; editing by Sandra Maler, David Storey and G Crosse)