I always thought Trump chose him as his own kind of insurance policy because if the let actually took him out they would get an actual right wing Christian in charge of the country.

But in retrospect he was probably permitted in the VP role because he was hardline deep state and was involved in all manner of child rapes and murders, so if they had to take Trump out, they would have someone who is in the fold to take over. It explains why he ended up being Brutus.