VATICAN CITY — There are few people you’re less likely to see at the head table of a Vatican conference than a secular feminist Jew.

But Naomi Klein, Canadian author of This Changes Everything: Capitalism vs. the Climate, didn’t feel out of place at all. She was in Rome to headline a conference called People and Planet First: The Imperative to Change Course.

In working with Klein, the Vatican clearly knew it could harness loyalists of one of the most influential voices in the climate movement. But Klein says she doesn’t feel used—because environmental advocates also win by tapping into fans of Pope Francis. “Who used who more?” she joked to The Daily Beast in an interview after the conference. “In reality, we all benefit if people are paying attention to the issue.”

The conference was almost like a celebratory book-signing party for the pope’s encyclical on climate issued in June. It’s also a topic that has the potential to divide the church almost to the same level as same-sex unions and what to do with divorced Catholics, especially when it comes to America’s reluctance to focus on global warming. “Given the attacks that are coming from the Republican Party around this and also the fossil-fuel interests in the United States, it was a particularly courageous decision to invite me here,” Klein said at a press conference. “I think it indicates that the Holy See is not being intimidated, and knows that when you say powerful truths, you make some powerful enemies and that’s part of what this is about.”

This week, Francis is taking the encyclical message on the road to Latin America, which should give an indication about who his enemies on climate are and how he plans to thump for climate change abroad despite that his 24,000-kilometer journey will leave a hefty carbon footprint. He will start a seven-day trip to Ecuador, Bolivia, and Paraguay, where, among other things, he is expected to chew coca leaves to combat altitude sickness.

He is also expected to enter the climate debate in one of the most complicated areas of the world, where heavy investment in fossil fuels has been vital to the economy for many, while making life much worse for others. And with predictions that regional electricity use will double by 2030, leaders are torn over whether to develop green energy options or dig up the wealth of coal, natural gas, and oil deposits many countries are sitting on.

After his Latin America trip, the pope will prepare for his September journey to Cuba and the United States, where he will no doubt be greeted warmly by the masses, but where he may also face bigger challenges when it comes to getting policymakers to think differently. There, he is expected to address both the United Nations and Congress to try to sell his encyclical ideals to a much tougher audience. It will be telling just who buddies up to the popular pontiff and at what cost.

He has already made an appearance, at least virtually, on the U.S. presidential election campaign trail. In Iowa last week, Catholic leaders called on GOP candidates to embrace the words of the encyclical on climate and income disparity with as much vigor as they have in previous fights against gay marriage and abortion.

U.S. Catholic bishops are weighing in early to sway potential contenders to adopt the Francis mantra—at least on climate issues. No doubt it doesn’t hurt that six Catholics are vying for the Republican nomination. While there is no chance Francis will officially endorse any of them, there is little doubt that they are all weighing just how closely to align themselves with the pope’s party line. Both Jeb Bush and Rick Santorum have distanced themselves from Francis’s take on the environment. “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 cardinal or my pope,” Bush said when the encyclical was released. “I think religion ought to be about making us better as people and less about things that end up getting in the political realm.”

Still, Des Moines Bishop Richard Pates wasted no time invoking Francis’s words to potentially sway Catholic candidates. “The goal of the pope is to raise the questions with all the candidates,” Rev. Pates said last week. “It’s a moral issue, our relationship with creation, our relationship with each other.”

It’s a message that’s a godsend for the climate movement, says Klein, who points out she isn’t on the Vatican payroll and isn’t about to convert to Catholicism. “The issue has been crying out for a strong moral voice for a long time,” she told The Daily Beast in Rome. “This will help people get out of their single-issue boxes that sometimes hold us back.”

She says no one can know just how the pope’s views on climate change will affect U.S. policymakers when he visits in September, “but there will definitely be an impact.”