WASHINGTON – Shortly before leaving the Capitol for the holiday recess, Senate Democrats gathered behind closed doors to lay out an agenda for 2014. When the majority leader, Sen. Harry Reid of Nevada, exhorted colleagues to “deal with the issue of income inequality,” the talk took a spiritual turn.

“You know,” declared Sen. Bernie Sanders, I-Vt., who caucuses with Democrats, “we have a strong ally on our side in this issue – and that is the pope.”

That Sanders, who is Jewish, would invoke the pope to Reid, a Mormon, delighted Catholics in the room. (“Bernie! You’re quoting my pope; this is good!” Sen. Richard J. Durbin of Illinois recalled thinking.) Beyond interfaith banter, the comment underscored a larger truth:

From 4,500 miles away at the Vatican, Pope Francis, who has captivated the world with a message of economic justice and tolerance, has become a presence in Washington’s policy debate.

As lawmakers return to the capital this week and mark the 50th anniversary of President Lyndon B. Johnson’s declaration of a “War on Poverty,” Democrats – including those Catholics whose politics have put them at odds with a conservative church hierarchy – are seizing on Francis’ words as a rare opportunity to use the pope’s moral force to advance issues such as extending unemployment benefits and raising the minimum wage.

“He has given a number of us in the political ranks encouragement, and really a challenge, to step up and remember many of the values that brought us to public life,” Durbin said.

Francis’ denunciation of an “economy of exclusion” goes to the heart of the debate between the two parties over the role of government.

Democrats such as Durbin and President Obama – whose administration is facing off against Catholic nuns in the Supreme Court over birth-control provisions in his health law – quote the pope in speeches, using his words to reinforce their positions. Republicans find themselves forced to justify votes to cut food stamps and unemployment benefits even as they try to counter the perception that they are indifferent to the poor.

Although the pope has caused unease among Republicans as they reconcile his critique of capitalism and “trickle-down theories” with their free-market views, some Catholic Republicans see opportunity in his words.

Rep. Paul D. Ryan, R-Wis., a potential 2016 presidential candidate who speaks of poverty in the context of his faith, has praised Francis for “breathing new life into the fight against poverty,” and is working on a Republican plan to address the issue. Newt Gingrich, the former House speaker and now a co-host of CNN’s “Crossfire,” said he would talk more about poverty on the program.

“I think every Republican should embrace the pope’s core critique that you do not want to live on a planet with billionaires and people who do not have any food,” Gingrich said. “I think the pope may, in fact, be starting a conversation at the exact moment the Republican Party itself needs to have that conversation.”

Catholic lawmakers in both parties know Francis is not changing church doctrine, including opposition to abortion and same-sex marriage. “I haven’t yet seen anything that departs from Catholic teaching,” said Sen. Patrick J. Toomey, R-Pa., an economic conservative.

In November, Francis issued a 51,000-word apostolic exhortation titled “Evangelii Gaudium” (“The Joy of the Gospel”), which decried “trickle-down theories” and the “dictatorship” of a free market that perpetuates inequality – views that some scholars attribute to his perspective as the first Latin American pope.

Obama approvingly quoted the exhortation in a speech on inequality, but radio host Rush Limbaugh, a conservative Republican, promptly accused Francis of spouting “pure Marxism,” setting Washington conservative policy circles abuzz.

“What Francis is saying goes to the soul of the party,” said John Feehery, a Republican strategist, who is Catholic. “What does the party actually believe in? What is its purpose? Is it just to have unbridled capitalism without any moral core?”

Ryan, chairman of the House Budget Committee whose 2012 proposal for cuts in social programs drew criticism from Catholic bishops, has tried to answer that question. In a speech titled “Free Enterprise, Faith and the Common Good,” he argued that free enterprise and the Catholic principle of “subsidiarity” – handling matters through the least centralized authority – can address poverty better than big government.

As to Francis’ “trickle down” comment, Ryan told the Milwaukee Journal Sentinel last month: “The guy is from Argentina, they haven’t had real capitalism in Argentina.”

For Democrats, the pope’s apparent progressive leanings provide a fresh point of entry to reach Catholic voters.

Still, some Catholic lawmakers sound uneasy, wary of appropriating a religious leader as their own.

“I don’t talk about the pope that much,” said Sen. Joe Donnelly, a freshman Democrat from Indiana.

“He’s not there to promote the Republicans or promote the Democratic Party. He’s there simply to preach the Gospel of Jesus Christ, and so the chips fall where they may when he does.”