Eight years ago, in the lead-up to the 2016 presidential election, JD Vance was a bitter critic of Donald Trump.

Publicly, he called the Republican businessman an "idiot" and said he was "reprehensible." Privately, he compared him to Adolf Hitler.

But by the time the former president tapped Vance to be his running mate in July, the Ohio native had become one of Trump's most ardent defenders. With Trump's decisive win in Tuesday's presidential election, Vance, 40, also became the heir apparent to Trump's re-energized Make America Great Again movement.