With Republican politicians (or at least their staffs) busy reading, pondering, and strategizing about how to respond to Pope Francis' encyclical on the environment, I'd like to propose that pundits and political junkies play a little game to liven the mood.

The rules are simple. Every time a Republican who is a Catholic is asked for an opinion on the encyclical, place him into one of two categories: the Catholic Republicans or the Republican Catholics.

The difference between the categories depends on which term is doing the modifying. A Catholic Republican is a Republican whose Catholicism comes first, whose faith and devotion to the teaching authority of the Magisterium of the church takes precedence when a conflict or tension arises between it and loyalty to the party's ideology, policy platform, and electoral prospects. A Republican Catholic, on the other hand, is a Republican who puts his devotion to the party ahead of his faith — or at least adjusts what he takes to be the demands of his faith in such a way that the conflict or tension seems to lessen or disappear.

This isn't a game that would have worked nearly as well under the previous two popes. John Paul II and Benedict XVI emphasized social issues (defense of traditional marriage; opposition to abortion, pre-marital sex, and contraception) in their rhetoric and public statements. Meanwhile, theoconservative intellectuals in the United States worked overtime to highlight other signs of continuity, and downplay any points of discontinuity, between Catholic social teaching and the Republican Party platform.

The point of these efforts was to convince Catholic members of the American conservative movement that they didn't have to choose: a good Catholic could be a good Republican and a good Republican could be a good Catholic. Indeed, it wasn't just that there was no tension between Catholicism and American conservatism; it was that each implied the other. Symbiosis, conciliation, and synthesis were the order of the day.

Pope Francis has brought that era to an end. Whereas John Paul liked to talk about the Republican-friendly concept of subsidiarity (having the most local possible public authority handle the administration of social services and welfare), Francis is quite comfortable endorsing state action to advance the common good and address significant social and economic problems. And whereas John Paul loudly denounced the "culture of death" (abortion, euthanasia) and Benedict railed against an incipient "dictatorship of relativism," both of which echoed concerns of the American religious right, Francis speaks more quietly and in a more nuanced way about social issues, while leading with issues on which the Catholic Church and the Republican Party have always been farthest apart — poverty, inequality, the damage wrought by free-market ideology, and now climate change and related environmental concerns.

All of which has made things much more complicated for Catholic members of the GOP, forcing them, on some issues at least, to choose between religious and political allegiances. That's not a fun position to be in, especially when Republicans have grown accustomed to thinking of the allegiances being not just compatible but self-reinforcing and electorally beneficial. The result can be painful to watch, as some Republicans who once acted like Catholic triumphalists dismiss the current pontiff's ideas and arguments, while others turn themselves into contortionists trying to make it all hang together.

And that brings us to our little game.

For our first Republican Catholic — once again, a Catholic who puts allegiance to the Republican Party first — who could be a better choice than Rick Santorum? Unlike Methodist Rush Limbaugh, Santorum doesn't go so far as to accuse the pope of having "fallen in with the communist way of doing things." But he does make it clear that the Holy Father's thoughts about climate change can be waved away: "The church has gotten it wrong a few times on science, and I think we probably are better off leaving science to the scientists and focusing on what we're good at, which is theology and morality."

As any number of critics have pointed out in response to this statement, Jose Mario Bergoglio was, in fact, a scientist (a chemist) before he entered the seminary. But that's a distraction from what's really significant in Santorum's claim — which is both that Republican Catholics can ignore what the pope says on anything that goes beyond the topics of theology and morality (narrowly defined) and that science is a topic with no significant theological or moral implications. I doubt Santorum would have said the same thing in the 1990s, when a pope more ideologically congenial to him powerfully pronounced on issues wrapped up with science.

Jeb Bush — an adult convert to the Catholic Church — has staked out a similar but possibly even more sweeping position as a Republican Catholic. According to The New York Times, Bush had this to say earlier this week in New Hampshire: "I hope I'm not going to get castigated for saying this by my priest back home, but I don't get economic policy from my bishops or my cardinals or my pope… I think religion ought to be about making us better as people and less about things that end up getting in the political realm."

Message: I'm free to ignore anything and everything the pope has to say about public matters, and that frees me up to put my Republican commitments ahead of my duties as a Catholic. John F. Kennedy once championed this apolitical vision of the church, and the theocons used to castigate him for it. (Here's Rick Santorum saying three years ago that JFK's 1960 speech defending this stance made him "want to throw up.") But now GOP presidential candidates are staking out the same position.

Robert P. George of Princeton University presents a more interesting case. An influential figure in Republican circles, George wrote a column in First Things last January in which he took a strong Republican Catholic position by assuring members of the party that they could safely ignore whatever the pope might say about climate change because his arguments would be based on contestable empirical claims about which Francis possesses no special expertise. But earlier this week, just days before release of the encyclical, George posted a short statement online in which he took a rather different stance, urging "Catholic friends" to receive the encyclical "in a spirit of willingness to listen and to be taught by the Holy Father." These were the words of a Catholic Republican.

Where will Catholics running for president as Republicans (or considering it) come down in the coming days and weeks? Will Bobby Jindal confirm his reputation as a conservative ideologue by coming out as a Republican Catholic? Will Marco Rubio try to demonstrate the depth of his faith by showing he's a Catholic Republican?

Keep watch, listen, and play along with the game.

You have nothing to lose but your naïveté about the way politics and religion interact in America.