The Georgia Republican seeks a sentence reduction, not a pardon, for Santos, who previously represented New York as a Republican in the U.S. House.

It might be hard to find someone to have your back in politics if you get caught lying about your life story, become one of a handful of people ever expelled from Congress and then are thrown into federal prison.

Ms. Greene, the hard-right House Republican from Georgia, called her former colleague’s seven-year sentence “excessive” in a letter to the U.S. pardon attorney.