With an estimated net worth of $30m, he may not quite be in the same league as the billionaire Republican presidential hopeful, but it's not just his considerable wealth that has led commentators to dub Alan Grayson the Democrats' answer to Donald Trump.

A largely unknown first-term congressman, Mr Grayson became an overnight hero to the US left when he took to the floor of the House of Representatives in September 2009 to attack opponents of Obamacare with the words: "If you get sick, America, the Republican healthcare plan is this: Die quickly."

Since then, Mr Grayson, who last month jumped into the race to become his party's candidate in next year's battle for Florida's highly marginal Senate seat, has continued to burnish his reputation as a Trump-like "hip-shooting firebrand". He's branded Republicans as "knuckle-dragging Neanderthals"; drawn parallels between the Tea Party and the Ku Klux Klan; and said of former US vice-president Dick Cheney: "I have trouble listening to what he says sometimes because of the blood that drips from his teeth while he's talking." Against that, Mr Grayson's description of his Republican opponent in 2010 as "Taliban Dan" seems positively tame.

Unsurprisingly, leading Democrats are not enthused at the prospect of a highly partisan, unapologetic liberal as the party's standard-bearer in a state that it will need to carry to retain the White House and retake the Senate in 2016. The party's leader in the Senate, Harry Reid, and the Democratic Senatorial Campaign Committee have already lined up behind Mr Grayson's centrist opponent, a two-term, 32-year-old former Republican, Patrick Murphy.

But Mr Grayson is not someone to underestimate. A Bronx-born Jew who worked his way through Harvard as a janitor and nightwatchman and then went on to become a multimillionaire lawyer, he has shown remarkable political resilience. Targeted heavily by conservative groups, Mr Grayson was defeated for re-election in 2010. Two years later, he was back in Congress after snatching a neighbouring seat.

Over the past two years, suggests one reporter, Mr Grayson has been "subtly trying to clean himself up for a state-wide race… staking out policy positions closer to the political centre that most Floridians occupy".

Moreover, with his strong support for Israel and opposition to both President Obama's Iran deal and opening to Cuba, the congressman has made sure to appeal to the state's sizeable Cuban-American and Jewish vote.

Not a man imbued with much self-doubt, Mr Grayson last month explained his appeal with the words: "One reason why Democrats are willing to crawl over hot coals naked to vote for me is because I'm willing to tell the truth."

Ultimately, though, that may not be enough. Mr Grayson's fate will be determined by whether Democrats vote with their head or their hearts. Mirroring the choice between Hillary Clinton and Bernie Sanders, they can play it safe with the establishment-backed centrist or opt for a sock-it-to 'em populist who fires up the party's base but stands a high chance of crashing and burning at the general election.