No matter how much you may wish, and fantasize, there will be no return to the days when it was "Popes" and Roman Catholic Church officers/politicians, who get to pick who is king, and who is not.
The only King "christian" religious authorities have proper right to call upon, is the Lord.
They overstepped their bounds in "going secular", making themselves to be the worldly king-makers in the past. History richly illustrates the mixed bag that brought the world. Thanks for the thought, though. I realize you are just trying to help, but no thanks all the same...