Never say politics isn't full of surprises. Last night's Republican debate in Michigan appears to have witnessed the end of one candidate's presidential campaign, but it wasn't Herman Cain who was brought down by the sheer weight of those sexual harassment allegations -- but Rick Perry, who fell victim to the most embarrassing kind of political amnesia.

The Texas Governor may be highly regarded in his home state, but on the national stage he's often come across as something of a joke, with poor performances in previous debates adding to a somewhat lacklustre campaign. Last night though, his fate was potentially sealed by a single word: "Oops".

The actual flub is almost too painful to watch. It was a kind of brain meltdown, as Perry struggled to list the three Government agencies that he would axe. After Commerce and Education, he just couldn't blurt out the third.

As the audience broke into guffaws Perry blundered on, but for the pundits, it was all over. Presidential scholar Larry Sabato called it "the most devastating moment of any modern primary debate". Ouch. Politico quotes an email from one high-level supporter simply stating "I'm sad. Stuck a fork in himself. Can't decide which is worse, Dean scream or Perry oops." On a more serious note, leading GOP senator Jim DeMint admitted "It is a problem. We need to stay on message."

Perry himself insisted his campaign was right on track -- and he's even been trying to make some political capital out of the gaffe, with a new fundraising letter to supporters. We all have human moments, it says, "and tonight Rick Perry forgot the third agency he wants to eliminate. Just goes to show there are too damn many federal agencies."

The candidate himself appeared in the spin room immediately after the debate with that same bluff-straight-through it approach. "I stepped in it out there", he told reporters. "I may have forgotten Energy, but I haven't forgotten my conservative principles."

But any candidate worth a dime wouldn't have had to show up in the spin room in person: it's not exactly front runner behaviour. To think that all those millions of dollars raised, all those endless trips to the furthest flung regions of Iowa and New Hampshire, should come to this: a man who now looks too stupid to win the Republican nomination.

There's just eight weeks to go before the Iowa caucuses -- not long to rebuild an image, not long to urge big-time donors to stay on board. Even in a contest which has been anything but predictable, it's not looking good for Perry. Take an email from one backer, who tries to list three reasons why he still supports him: "He really is, ah... I'll get back to you on the third". "Oops" Apocalypse, as you might say.

Felicity Spector is a senior producer at Channel 4 News.