I actually think a more interesting question is when we’ll finally have an agnostic or atheist president.
It’s convenient for politicians to identify with the religion they were raised in, especially if it is a mainstream religion, even in Europe. 25% of millennials self-identify as “none” for religion. Many elected officials are older, the torch is currently being passed from the Boomers to Gen X. It’s going to be interesting to see when the Millenials start electing openly non-religious candidates to high offices.