true believer

noun

1. a person who has been thoroughly convinced of something.
2. a fanatic, especially a religious or political one.

Example Sentences

"Pete has spent his entire life as a Warrior for the Troops, and for the Country. Pete is tough, smart and a true believer in America First. With Pete at the helm, America’s enemies are on notice," Trump said in a statement announcing his choice.

From BBC

“Pete is tough, smart and a true believer in America First,” Trump said Tuesday as he announced the nomination on TruthSocial.

From Los Angeles Times

Announcing his choice on Tuesday, Trump described him as "tough, smart and a true believer in America First".

From BBC

“Pete is tough, smart and a true believer in America First,” Trump said in his statement announcing the appointment.

From Los Angeles Times

Bonar Law was both a true believer in the Ulster cause and a shrewd political operator, who correctly perceived that home rule could be used to bring down Asquith and the Liberals.

From Salon