Fred Karger walked into a coffee shop in Manhattan looking every inch the sort of man who wants to be a Republican presidential candidate.

The long-time "Grand Old Party" operative, who has served three different Republican presidents, had close-cropped grey hair and wore a sharp blue business suit. He clutched a folder of campaign literature and handed out a T-shirt emblazoned with "Iowa 2012". But one key detail made Karger a little different in a Republican field swirling with names like Jeb Bush, Mitt Romney, Sarah Palin and Mike Huckabee. On his suit lapel Karger wore a badge pairing the Stars and Stripes with the rainbow colours of the gay rights movement.

Karger, 61, whose 2012 presidential exploratory committee is perhaps the furthest advanced of any potential Republican candidate, is openly gay. When he officially declares his run, he will not only be the first gay Republican presidential candidate but also the first such candidate from any political party in American history.