Sen. Tim Kaine (D-Va.) speaks during the official opening of the new I-95 Express Lanes, Wednesday, Dec. 10, 2014, at the Express Lanes Operations Center in Alexandria, Va. (AP Photo/Molly Riley)

When Pope Francis stands before Congress on Thursday, he will not only be addressing the world's most powerful legislature, but he will also be addressing 165 members of his church flock.

Nearly one-third of Congress is Catholic, and they are almost evenly divided between Republicans (82) and Democrats (83). But that shared faith has not meant much in the way of common political ground, with Catholic lawmakers split along much the same partisan and ideological lines as the public at large.

At the White House on Wednesday, Francis said members of Congress can expect to hear "words of encouragement." But two Catholic senators are hoping for two sharply different kinds of encouragement.

Tim Kaine (D-Va.) and Mike Rounds (R-S.D.) are both devout Catholics in their first Senate terms, and both former governors who faced politically momentous decisions that were deeply entangled with their faith.

Mike Rounds (R-S.D.), seen in a file photo taken during his 2014 Senate campaign. (AP/Dirk Lammers)

Kaine vetoed numerous state bills that would have expanded the death penalty in Virginia but stood aside, with considerable anguish, as executions were carried out during his term. In 2006, Rounds signed the nation's most restrictive state abortion law, which essentially banned all abortions except in narrow circumstances to save a mother's life. The law, which was designed to force the Supreme Court to reconsider Roe v. Wade, was later repealed in a voter referendum.

With Francis expected to urge action on issues that have sharply divided lawmakers along partisan lines -- immigration, economic inequality and, above all, climate change -- the two men have diverging expectations for the papal address.

Rounds cited "some trepidation on the part of some of us who are conservatives" in an interview Wednesday. "We've heard all the rumors about how he's really excited about trying to do something about climate change. ... We think there's misunderstanding where it sounds like we don't care about the environment. It isn't that any of us want to see the environment damaged; it's a matter of, how do you, on a long-term and sustained basis, make the right tactical moves to get that job done?"

From his private meeting with President Obama to giving the first-ever papal address before a joint session of Congress, Pope Francis did not shy away from politics during his three-day stop in Washington, D.C. (Julie Percha/The Washington Post)

For Kaine, who spent two years as a young man serving in a Jesuit mission in Honduras, trepidation does not figure into his reaction. "I've waited my whole life for this," he said Tuesday. "If you told me that in my life I would see a Latin American, Jesuit pope at a time when [Pope John Paul II] was frankly kicking around a lot of the Latin American Jesuits ... I just would have been stunned."

Kaine said he was "very, very excited" by "Laudato Si," Francis's encyclical on the environment generally and on the need to address climate change in particular -- something Kaine places in "an area of fundamental truth."

"I'm sure he's not going to opine on whether a carbon tax is better than a cap-and-trade mechanism," he said. "That doesn't need to be where he goes -- but to say, 'You know, you guys and everybody in power these days, you've got the next generation's future in your hands, and you don't want to have to face that question later in life: With the science what it was, and with you having the opportunity to do something about it, why did you choose not to?'"

But Rounds -- whose given name is Marion, in honor of the Holy Mother -- sees a potential conflict between Francis's focus on climate change and his oft-repeated calls for greater attention to the poor.

"I appreciate his message," Rounds said. "Now it's up to us to try to look at what we think are the most sustainable ways in which we could find the right tactics, so to speak. ... That's where we're having our disagreement. Does it mean you shut down [coal power plants] and increase the price of electricity for those who are poor? Do you raise the cost of electricity across the United States? Or do you find new technologies or new alternatives?

"In my part of the country," he continued, "it gets down to 30 degrees below zero. ... I've got folks who live on Indian reservations that are below the poverty level. They worry about just keeping their homes heated, let alone what the cost of it is or whether it is coming from a coal-fired plant or if it's coming from windmills. We have both, but if we rely strictly on the renewable sources available to us today those folks would never be able to afford the cost of that power."

Kaine, who speaks fluent Spanish, is also hoping the Argentine pope will bring attention to what he calls a "Hispanic moment" in America. "People are kind of kicking around immigrants as if Hispanic immigration is something new. Well, no, [the Spanish landing in Florida] was 42 years before Jamestown. We've got people saying to others, 'Hey, speak American.' Well, Spanish has been spoken here longer than English. And then we have this Latin American pope coming in the middle of all of these things. It's just an amazing convergence."

Both men agree on this: Francis has a remarkable ability to connect with people regardless of ideology, politics or faith.

"There's something in the tenor of his voice," Rounds said. "It's one of sharing and one of teaching and not so much one of trying to suggest that he has all of the answers. He's simply pointing out that there is more that could be done."

"Why do non-Catholics like Francis? Why has he grabbed their imagination?" Kaine asked. "He really is trying to exemplify the humility of service as requisite for leadership, and very few leaders really demonstrate that these days. The church desperately needed that, but the world needs it, too."

Kaine says flattery will get Francis everywhere if he wants to get through to his powerful and largely wealthy audience in Congress: "Say, 'Hey, look, here's the way we think of you Americans: You rebuilt the economies of your war-ravaged enemies after World War II. That was a magnanimous thing you did, and the world needs that every bit as much today as it did then.' ... They're mad at us about other things, but when the chips are down and there's a big problem, we're often the party that gets asked. ... We do that, and we do that willingly, and we like it when somebody notices. So I think the pope can do that and call us to do even more."

And he has some advice for his colleagues, too: Cut the politics out of it.

"We should just go in and listen to him and be surprised," Kaine said. "It's like the biblical parable of the seed. Does it fall on rocky ground? Does it fall on shallow soil? Or does it fall on good soil? Let's just be good soil."