The U.S. presidential election cycle is about to step up a gear as Republican candidates prepare to face voters who’ll decide who gets their nomination.

Former President Donald Trump is the outright Republican frontrunner, and in the latest polls he’s ahead of Democratic Party incumbent, Joe Biden.

But Trump’s disqualification from the Republican primary ballot in Colorado and Maine makes his candidacy uncertain.

That’s where things start to get complicated, as CGTN’s Owen Fairclough explains.