The race is hotting up between Democrat rivals Hillary Clinton and Bernie Sanders ahead of the Iowa caucus on 1 February, with Sanders closing in on Clinton's lead.
And fans are doing all they can to support their candidates.
First there was Bernie Sanders' own Ben and Jerry's ice cream flavour, called "Bernie's Yearning" and subtitled Vermont's Finest Senator.
But now supporters are stepping up their efforts too, with a spectacular range of merchandise. One avid fan turned up to a rally on Tuesday in quite stunning attire.
And in Vermont, the home state of Sanders, one company has sprung up to sell "Bernie's Briefs".
The company said that in recognition of Bernie’s lifelong dedication to helping veterans, 10 per cent of all profits will go to the Yellow Ribbon Fund, a charity that helps returning American servicemen and women.
Ahead of the Iowa caucus, the margin between Sanders and Clinton in Iowa has closed to its narrowest point yet, as Clinton's lead shrunk to below 50 per cent. A recent Fox poll puts Clinton on 49 per cent of the vote, down from 54 per cent, while Sanders is on 37 per cent.
Of course, if you're more inclined to vote Republican, you can always dress up as Donald Trump. His trademark hat is on sale at a variety of outlets.
More importantly, though, is the Donald Trump wig. Better move fast on these though: retailers are reporting high demand...