They have 100 billion in a “wealth fund” for the church, about 40% of which is in the US stock market.

The members of their church are also incredibly submissive and will do whatever their church leaders say, including voting.

Republicans have a very thin majority in both the House and Senate.

Losing the Mormon church, would mean trump loses majority in both. And would prevent a Republican from becoming president.

They’re a very large and important bloc of the Republican party.