VATICAN CITY — Two close associates of Pope Francis have accused American Catholic ultraconservatives of making an alliance of “hate” with evangelical Christians to back President Trump, further alienating a group already out of the Vatican’s good graces. The authors, writing in a Vatican-vetted journal, singled out Stephen K. Bannon, Mr. Trump’s chief strategist, as a “supporter of an apocalyptic geopolitics” that has stymied action against climate change and exploited fears of migrants and Muslims with calls for “walls and purifying deportations.” The article warns that conservative American Catholics have strayed dangerously into the deepening political polarization in the United...