When the cardinals enter the Sistine Chapel on Wednesday at the start of conclave, the process of electing a new pope, they will be sealed off from the world.

A papal conclave blends the political and the spiritual, cardinals and theologians say. Here, in Catholic belief, is how the Holy Spirit fits in.

The United States is the home country of 10 of the 133 cardinals eligible to vote for the next pope of the Catholic Church. That's more than any nation except Italy, home to 17 of the electors who will gather at the Vatican's Sistine Chapel on Wednesday for the conclave that will choose a successor to Pope Francis.