The race to become the Democratic Party’s top pick to beat Donald Trump is under way – and the latest polls show anything can happen.

Just as Bernie Sanders, Elizabeth Warren and Joe Biden were starting to get comfortable as frontrunners, late-entrant Michael Bloomberg surged in popularity on Tuesday.

The billionaire, 78, skyrocketed to second place in the polls after pouring millions of dollars of his money into a national advertising campaign. 

Tuesday’s poll, released by National Public Radio/PBS NewsHour/Marist, showed Mr Bloomberg had support from 19 per cent of the people surveyed, placing him behind favourite Mr Sanders (31 per cent).

Mr Biden, whose recent drop in polling has accompanied Mr Bloomberg’s rise, was third at 15 per cent.

Senator Warren was fourth at 12 per cent, followed by Amy Klobuchar (nine per cent), and Pete Buttigieg (eight per cent).

The rest of the Democratic hopefuls came in at 2 per cent or less.

Given Mr Bloomberg chose not to compete in the first four nomination contests – Iowa, New Hampshire, Nevada and South Carolina – his new position as a serious contender has come as a surprise.

The former New York Mayor’s success in the recent poll means he will quality for Wednesday’s Nevada debate, his first debate this year.

There are now eight candidates vying for a shot at winning the final presidential nomination.

Who are the frontrunners? What do they care about?