In reference to the issue the Pope has with a nation keeping it's borders: https://edition.cnn.com/2016/02/18/politics/pope-francis-trump-christian-wall/
Evidently he wants exclusive rights to keep people out of his territory.
The Pope would later revise his statement, saying "In no way was this a personal attack, nor an indication of how to vote." It would seem that there is more he fears than just God's wrath.
