Donald Trump won the Iowa caucuses earlier this week, cementing him as the frontrunner in the 2024 Republican race to become the party’s next presidential candidate.

It's the first step towards another expected showdown between Donald Trump and Joe Biden. But it’s not yet guaranteed that both the current President and former President will face off. They need to go through the long, public selection process. In today’s deep dive, we’ll explain how American political parties choose their candidates for President.