Trump grants clemency to a dozen lawmakers convicted of corruption

A presidential pardon wipes out a criminal conviction, while a commutation only reduces the sentence but leaves the conviction intact.

Bill Clinton's pardon of fugitive billionaire Marc Rich on his last day in office sparked such controversy that it led to congressional hearings and was criticized as "indefensible" across the political spectrum.

Former Rep. Duncan Hunter (R-CA) spent more than $150,000 in campaign funds on personal expenses including family vacations and a garage door, then blamed his wife.

President Gerald Ford's approval rating dropped from 71% to 50% immediately after he pardoned Richard Nixon in 1974, and historians believe the controversy cost Ford the 1976 election.

The Office of the Pardon Attorney in the Justice Department reviews clemency petitions and recommends candidates to the president, but presidents can ignore these recommendations and pardon anyone they choose.