AS THE US presidential primary campaigns kick into higher gear, the contest could herald the return of political instability in the world’s largest economy.

Democratic President Joe Biden is as vulnerable to a party challenger as any post-war sitting president. Meanwhile, the Republican party is set for a bitter fight, as Florida’s Governor Ron DeSantis tries to prise the Grand Old Party from Donald Trump’s grip. Whatever the outcome, the rancour aroused in these contests is set to test American democracy once more.

The Biden presidency has so far been a welcome reprieve of relative comity during an era of steadily fraying democracy. Legislators have not exactly joined hands across the aisles, but the heckling has mellowed somewhat.