It might be two months since the US Supreme Court's historic ruling legalising equal marriage across all 50 states, but it seems some people just aren't willing to admit defeat. Four Republican presidential candidates have signed a pledge committing them to overturning the ruling and banning same-sex marriage completely in a new constitutional amendment should they be voted into the White House in 2016. The pledge also commits them to banning the the 'promotion' of same-sex marriage US public schools, as well as directing the Justice Department to investigate the supposed harassment of gay marriage opponents. Ted Cruz, Ben Carson, Bobby Jindal and Rick Santorum have all signed the National Organization for Marriage’s (NOM) presidential candidate pledge, Right Wing Watch reports, though thankfully none of them are considered frontrunners in the race. The group's president, Brian Brown, said in a statement: "NOM has invited every candidate for president to sign our pledge, and we encourage those who have not yet signed to do so as soon as possible. "While many of the GOP candidates talk the talk about supporting marriage, these four candidates have distinguished themselves as true champions, having pledged to the American people to take very specific actions to advance the cause of marriage." Meanwhile the race's unlikely frontrunner, billionaire tycoon Donald Trump, was recently given a fierce drag makeover by an artist in a hilarious new video - click here to check it out