PHILADELPHIA – To be sure, Pope Francis did not come to the United States primarily to deliver a political message but to act as a pastor, encouraging Catholics to hold on to their faith and to put it into action. Like a mantra, he has told them over and over, “Go forth!”

Equally surely, however, politics has been part of the mix.

From his remarks on the South Lawn of the White House on Wednesday to his addresses to a joint meeting of Congress on Thursday and the United Nations on Friday, the pope has presented a bushel basket full of policy concerns, ranging from immigration and climate change to arms trafficking and the death penalty.

Francis has already changed the political landscape by apparently giving House Speaker John Boehner, second in the order of succession to the presidency, the interior peace to decide to resign.

As the trip enters the final stretch this weekend in Philadelphia, however, it’s possible that the most important long-term political subtext is still to come.

In a nutshell, here it is: Francis may be the one man capable of converting American debates over religious freedom from an ideological matter to a universal cause that brings together both right and left.

We’ll get a more clear sense of that on Saturday, around 4:30 p.m. Eastern time, when Francis speaks at a “Meeting for Religious Liberty” at Philadelphia’s Independence National Historical Park, which includes members of the burgeoning Hispanic and immigrant communities in the United States.

How could Francis change the political calculus?

Up to this point, religious freedom is an issue in American politics that’s been largely a conservative cause. That’s because the flash points generally are drawn from the wars of culture and involve matters such as contraception and gay marriage.

Just yesterday, for instance, the county clerk in Kentucky who became the face of opposition to the Supreme Court ruling opposing gay marriage by refusing to issue licenses to same-sex couples, and who spent five days in jail, announced she was leaving the Democratic Party to join the Republicans.

“My husband and I had talked about it for quite a while, and we came to the conclusion that the Democratic Party left us a long time ago, so why were we hanging on?” Kim Davis said.

Davis had been elected as a Democrat, following in the footsteps of her mother who held the same job for 37 years and was also a Democrat. Tellingly, the news of her shift broke as Davis was in Washington for a meeting of the conservative Family Research Council.

What the defection illustrates is the perception in the United States that if you want to object to permissive legislation on the basis of your religious faith, then the Republicans are your natural home.

Similarly with regard to the US bishops’ ongoing struggles with the Obama administration over the contraception mandates imposed as part of health care reform, most of their support has come from conservatives disenchanted with Obama for a variety of reasons, while liberals have largely backed the president.

Facing that landscape, and knowing that when an issue becomes so intensely polarized it’s difficult to get anything done, what would a savvy tactician do? He or she would likely try to find ways to package the cause in a way calculated to appeal to the other side, which in this case means the liberals.

Enter Pope Francis, stage left.

First of all, Francis has credibility on the left for obvious reasons. The policy issues with which he’s most closely identified, especially poverty relief, climate change, and immigration, are their signature crusades. He also burnished those credentials before Congress by lifting up figures such as Dorothy Day and Thomas Merton, long seen in Catholic circles as liberal icons.

Moreover, Francis also has enchanted the left by perceptions that he’s moving the Church in a kinder, gentler direction, away from acting as a Catholic version of the Moral Majority.

Second, Francis has demonstrated a keen understanding of American culture during this trip, which is fairly remarkable for someone who’s never been here before and doesn’t really speak the language. (What that proves is both that Francis has had good advice, and that he was smart enough to take it.)

On Friday in New York, the pontiff could not possibly have delivered a more symbolically evocative set of performances: After his UN speech, he visited Ground Zero for a moving interfaith ceremony, turned in a tour de force at Our Lady Queen of Angels School in East Harlem, took a swing through New York’s backyard in Central Park, and finished up by playing the Garden.

If Francis can show the same deftness by linking the religious liberty issue to great American causes near and dear to the heart of the left — the civil rights and women’s rights movements, for instance, or the abolition of slavery — he could not only change minds, but drive votes.

Saturday afternoon, we should get an indication of whether that’s the direction Pope Francis intends to go when he speaks outside Independence Hall. If he does, America’s Catholic bishops, and those with religious objections to same-sex marriage, contraception, and other issues, stand to benefit.