Trump s Republican colleagues in the race for the US presidency, such as Ted Cruz, Ben Carson, and Marco Rubio, stoke similar fears about refugees. Cruz, as well as the supposedly more moderate Jeb Bush, even suggested that only Christians should be allowed into the US.

Francis will undoubtedly discuss the subject in his address to Congress, 30 of whose members including House Speaker John Boehner, a Republican are Catholic. Given that several of the leading candidates for the Republican presidential nomination including Jeb Bush, Marco Rubio, and Bobby Jindal also are Catholic, Francis s strong stance on climate change may create a serious political dilemma for some.

Ambitious young pols like Florida Senator Marco Rubio and Wisconsin Governor Scott Walker currently are viewed as Bush s strongest rivals, but both will be facing increased scrutiny and testing. Rand Paul enjoyed a period of buzz, but that seems to have faded, as his dovish brand of libertarianism clashes with a party that leans toward social conservatism and interventionism abroad.

So far, the only US presidential candidate who has recognized the need for such a future oriented approach is former Florida Governor Jeb Bush, who has proposed modernizing reforms of Social Security and Medicare that avoid imposing high costs on middle income Americans and a heavier debt burden on future generations. Two other Republican candidates, Ohio Governor John Kasich and Florida Senator Marco Rubio, have also raised constructive reform ideas.