In 1954, Congress was in the middle of a massive overhaul of the federal tax code. Then-Senator Lyndon Johnson slipped in an amendment prohibiting church pastors from supporting or opposing candidates.
Why would he suddenly take an interest in that? He was running for re-election that year.
His opponents had begun telling church members about his liberal record and the act of voter fraud that gave him an 87-vote statewide victory in the previous election.
So, he made talking about him in church illegal. The Johnson Amendment was speech suppression, pure and simple.
Pastors can't speak in support of or opposition to political candidates because 63 years ago a corrupt politician wanted to mess with Texans.