Washington, Jan 3 : Former US President Donald Trump's criminal cases of tax fraud and election subversion in his crushing calendar of legal obligations is set for a head-on collision with the race to the Iowa caucuses in two weeks' time that will decide the trend on who GOP will eventually nominate for the presidency in 2024. However, Trump still holds the wild card against his rivals Nikki Haley and Ron DeSantis.

With the courtroom and campaign trail demanding his presence in equal measure, they will compete with each other curtailing his campaign tours of states. It will set the tone for an unprecedented White House race overshadowed by the former President's four looming criminal trials, poll strategists and election experts say.

The US is about to embark on a political litmus test that will put the country's unity, democracy and legal institutions under duress, CNN analysts wrote.

Trump has drawn up his calendar for the first days of his 2nd term as President, should he win 2024, to punish his political enemies and most likely use his presidential authority to duck accountability for his "attempt to steal" the 2020 election in Washington DC and Georgia, where he is facing criminal charges.

The 2024 presidential race may even run the dubious distinction of seeing Trump, the GOP front-runner, contest as a convicted felon in November, all depending on his trials' timings and if he secures the GOP nomination.

The most likely scenario in November is a tight rematch between Trump and Biden. Most polls show most voters don't want this 2020 contest to repeat. They don't want either Trump or Biden and may pitch for a third-party candidate such as Robert Kennedy Jr, grand nephew of John F. Kennedy, making uncertain who the winner could be.

Trump is betting heavily on Iowa, where he failed in 2016, to make an extraordinary comeback to the national mainstream of politics amid his mounting legal woes. DeSantis hopes to beat him against all odds in Iowa and Haley hopes to secure New Hampshire, as both hope to close the ranks with the frontrunner.