Preamble: Welcome to tonight's Republican presidential candidates debate in Iowa – or, if you prefer, the competition to decide who will get beaten by Rick Perry for the 2012 Republican nomination.

On stage at Iowa State University in Ames tonight are the eight people battling for the nomination. But not on stage – and looming over proceedings like that guy in No Country For Old Men – is Perry, the governor of Texas.

It now appears certain that Perry will announce that he's a candidate as of Saturday in Charleston. And that changes everything, since Perry is a bigger presence than any of the puny earthlings at tonight's debate.

So it kind of makes you wonder what the point of this is. Except that for the eight on stage, it's their last chance to make an impression before Perry enters the race. They should, therefore, go at it like rats in a sacks. (And by that I mean fighting, not having sex.)

Apart from Perry there is another absent figure haunting this debate like Banquo's ghost – St Sarah of Wasila, the patron saint of pipelines. The former governor of Alaska was said to be running for the nomination. But then during a bus trip across America in June she disappeared and has not been seen since.

Palin's supporters have been out in force and many claim that she will appear among them in Iowa, for so it has been prophesied on Palin's Facebook page.

So who is actually on stage tonight? Here's a quick run-down:

Mitt Romney: currently the Front-Runner In Name Only (FRINO), the former Massachusetts governor leads the polls. But if you've got a poll, throw it away, it's worthless. After Saturday the polls will just say: "Rick Perry. The end."

Michele Bachmann: Bachmann was said to be the winner of the last debate, which was roughly a million years ago in June, so no-one cares. Currently on the cover of Newsweek looking a bit mad.

Jon Huntsman: A first appearance for the former governor of Utah, who graciously left the governor's mansion to serve his country as the US ambassador to China. Naturally he's as popular as anthrax.

Newt Gingrich: Less popular than anthrax.

Ron Paul: Iconic, veteran congressman, principled, intelligent. He has no chance. Quite the libertarian, except for abortion and gays. Then he's not. Seriously, he would win the nomination but for a secret alliance of the Mainstream Media, Wall Street and Republican voters who insist on not voting for him in large numbers.

Rick Santorum: Is he still running? I forget.

Herman Cain: Pizza guy. Meh.

Gary Johnson: According to NPR: "the former New Mexico governor will be a curiosity since most people still don't know who he is". I know he was governor of Mexico. Sorry, New Mexico. (Actually, he'd have more chance of becoming president of Mexico. Maybe he should try?) In fact Johnson is smart, sensible, was a very good governor and seems like a nice guy. Obviously: zero chance. Update: No, Gary Johnson's not in this debate. Whoops. I blame the internet.

Tim Pawlenty: Still running. May as well not bother. Seriously, have you seen his latest poll ratings? He's now less well-known than when he started. That's quite an achievement: negative publicity.

Anyway it all kicks off at 8pm in Iowa, which is 9pm ET, or 2am BST.

For British viewers – assuming the government hasn't cut off the internet to end the rioting yet – Fox News appears to be live-streaming video of the debate right here.

If you are bored waiting until the debate starts, here's the liveblog of the last debate back in June. It was a scream. Seriously, just screaming, basically.

On second thoughts, don't read it. I want to use the same jokes.

I thought at the time that Tim Pawlenty did well but Serious People said he didn't because he failed to rough up Mitt Romney when it mattered and now everyone thinks he's a wimp.

Rick Perry won't be on stage tonight – but we have the next best thing.

During the debate we shall be supplying "answers" from the popular Twitter account @RickPerryFacts, a compendium of Rick Perryabilia, such as:

Gravity doesn't exist. Rick Perry just prefers everything to stay the f*** down. Birds and planes exempt for unknown reasons. Rick Perry is better than the leading brand. Every leading brand. Gold tried to buy Rick Perry to hedge against inflation.

Here's a piece I wrote about Perry a while back.

Here we go: it's the start of Project Runway. But for the rest of you, it's the Republican debate.

I'll also be tweeting shorter versions of this on Twitter – you can follow me @RichardA – if you can't be bothered to read a whole live-blog.

So: the Fox News guys are introducing the candidates, briefly. Now the moderator, whatshisname, is banging on about the economy and the financial markets and how bad things are.

"We are asking you, the candidates, to put aside the talking points," he says. Oh yeah.

Almost immediately the candidates fail to put aside their talking points and start laying into Barack Obama, a soft target here tonight.

Mitt Romney reels off a list of stuff he'd do to fix the economy, which runs on to "Number seven...."

Meanwhile, on @RickPerryFacts:

Rick Perry doesn't turn the economy around, the economy revolves around him.

Romney is asked why he was such a wimp over the whole debt ceiling thing, waiting until five minutes before the vote before coming out against raising the debt ceiling.

"I'm not going to eat Barack Obama's dog food," Romney says when pressed. Quite what that means, no one knows, except that it sounds tough. This is obviously the Mean New Romney on show here tonight. Interesting.

Ron Paul! Is given longer than 30 seconds to explain his ideas, but stutters when asked how he would get it through a divided Congress.

"You can't cut one nickel from militarism around the world ... If you have to cut, let's cut militarism," says Ron, to surprisingly large applause. Militarism? Who are these hippies?

On the economy, Herman Cain says: "The tax rates need to be made permanent." Really not sure what that means.

Jon Huntsman gets to answer his first question in a presidential debate, and he talks about his record in Utah, although he has to confess that his campaign doesn't yet have an economic policy (Fox News having cunningly done research by looking at Huntsman's website.)

@RickPerryFacts:

Jon Huntsman? Rick Perry hunts, man.

Gingrich, asked the same thing, starts talking about ... Ronald Reagan's tax cuts 30 years ago. Highly relevant. I think Newt is running for the 1988 Republican nomination. (Bad news: Bush wins.)

Tim Pawlenty repeats his talking points from last time, but this time says that if anyone can find Barack Obama's economic plan, he'll cook them dinner – or cut their lawn, although he says if it's Mitt Romney, "I'll only cut one acre. One acre."

This is reference to Romney's vast wealth. Asked for his response, Mitt just laughs: "That's fine." He can afford to brush off Pawlenty, given his poll ratings.

Now Chris Wallace of Fox News asks: Tim Pawlenty why did you hate Michele Bachman, hmm?

Pawlenty says she's not as highly qualified as himself, a former governor of Minnesota. Complete silence from the crowd. Tumbleweed.

Now Bachmann's laying into Pawlenty's record with an axe, concluding: "That sounds a lot more like Barack Obama's record." Oooh.

Wallace responds: Isn't that about the worst thing you can say about a fellow Republican, that they are as bad as Barack Obama? Bachmann's not having it, and has another go at Pawlenty.

"I'm really surprised Representative Bachmann would say those things," whinges Pawlenty, before making some insane argument that Bachmann has been ineffective because she didn't somehow control Congress at the time. This is getting really nasty.

"I was at the tip of the spear fighting against the implementation of Obamacare," says Bachmann. And really, Pawlenty's a fool – there's no question that Bachmann has been a thorn in the side of the White House.

A boxing referee would call this off.

Ad break! Phew.

And we are back, and Wallace asks Newt Gingrich, how come if your campaign is in the ditch, how can anyone thinks you could be president?

Gingrich makes a nasty response about "gotcha questions" and then reels off a list of his crappy ideas that no-one is interested in.

Fox News debates are always the best.

@RickPerryFacts:

Rick Perry stole all of Newt Gingrich's staff. #forreal

It's true, he did.

Another tough question, this time for Huntsman, about being appointed by Obama as ambassador to China. Huntsman says he's proud of his service to his country. That's all very well but it's the albatross around his neck.

It's immigration now, the point at which the Republicans all queue up to say they love immigrants except the illegal ones. Who can't vote, sadly.

Herman Cain is asked about his lack of knowledge. But Cain says he knows plenty now about Israel and Palestine. "I've been documented," he says proudly. How exactly isn't clear. Did he pass a test or something?

On immigration, Cain says: "I want America to have high walls and open doors."

My colleague Ewen Macaskill is watching the debate at Iowa State University, and he notes the fist-fight between Pawlenty and Bachmann is all about the Iowa straw poll on Saturday:

Great to see Bachmann and Pawlenty getting personal early on. All jibes rehearsed but fun nonetheless. Liked Bachmann comparing Pawlenty's record to Obama's. It seems odd to me that when you have access to a national audience, the two of them are basically fighting for the small number of Iowans who will vote in Saturday's straw poll.

At last, someone is asking the tough questions about Minnesota's state cigarette tax. It seems Pawlenty actually raised a tax on something, a mortal sin in today's Republican party. And Michele Bachmann voted for it in the Minnesota state senate. Good god.

But Bachmann has an answer: she voted for the bill because ... there was something in it that "stripped protection from the unborn" unless she voted for the cigarette tax. Does that make sense? Anyway, Bachmann and Pawlenty have a back and forth and back again because we are all so interested in Minnesota state politics from the early 2000s.

Right now, a team of New York Times journalists are buying plane tickets for Minneapolis. Expect 10,000 words on the subject in about two weeks.

Rather depressingly, all candidates are asked if they would vote for tax increases if there were ten times as many spending cuts? All of those asked say no. Which, really, is insane.

Ewen Macaskill writes:

The personal spat between Bachmann and Pawlenty reminds me of when Clinton and Obama went at each other in Myrtle Beach debate. But Clinton and Obama was a real blast of temper and loss of control on both sides. Pawlenty and Bachmann were prepared for this.

Pawlenty is offered another chance to have a go at Romney's healthcare record, the one he dubbed "Obamneycare" and then wimped out on in the last debate.

Once again, he drops the ball.

More from @RickPerryFacts:

RickPerrycare consists entirely of Rick Perry donating his own plasma and stem cells to the sick and injured.

Oh, Chris Wallace has led Romney down a rabbit hole here – asking him where in the US constitution does it allow the government to compel people to purchase something (such as mandatory health insurance). Romney says oh well, according to the Massachusetts constitution, yes you can.

Wallace then asks Bachmann if she agrees – offering her a free shot at Romney, which she doesn't quite take.

Ron Paul kind of backs up Romney, says the federal government can't stop state governments from doing bad things (well, the Supreme Court says otherwise in a number of cases, but never mind).

Oh and now Rick Santorum (yes, he's here) gets passionate, saying "states don't have the right to do wrong", quoting Abraham Lincoln there. The reason he says that is because he wants to federally impose bans on abortion and homosexuality, and the idea that states might have rights doesn't appeal to him, despite the 10th amendment.

Anyway, that's his Tea Party vote gone.

Now it's back from an ad break – and there's no Michele Bachmann? Her podium is empty. But then she's back.

Now the candidates are actually being asked about Rick Perry entering. Based on their responses, they all think it would somehow be good for them. Losers.

Larry Sabato, the political sage of the University of Virginia, opines via Twitter:

It's too early to declare a winner, but if you forced me, I'd say: Rick Perry.

Oh dear. Now we're on Afghanistan, and Tim Pawlenty refers to Admiral Mullen, the chairman of the military chiefs of staff, as "General Mullen". Fail.

Gingrich is complaining again about the questions he's being asked. He is doing nothing to dispel the widely-held view that he is a giant wind-bag.

The serious point was that he was asked to explain his shifting position on Libya – which tied him up in knots – and Gingrich bangs the "gotcha question" drum once too often.

His latest campaign tactic is obviously "be a prick". If so, he's succeeding magnificently.

I think – based on his current answer – Ron Paul wants to actually give nuclear weapons to Iran. Now that's thinking outside the box!

"We tolerated the Soviets, we didn't attack them," says Ron. "It's about time we talked to Cuba and stopped fighting these wars that are about 30 or 40 years old."

Oh dear, all this just gives Santorum a chance to get all po-faced about "the threat from Iran".

"The senator is wrong in his history," says Ron Paul, pointing out the US's long involvement in Iran. "It's being going on and on because we just plain can't mind our own business."

And people wonder why Ron Paul can't get Republicans to vote for him. Maybe he should run in the Democratic primary?

This gives Herman Cain the chances to show off his newly-gained PhD from SAIS on foreign policy. Sadly, it's all nonsense.

Ron Paul now whaling on Michele Bachmann for denying Miranda rights ("You have the right to remain silent..." etc) to terrorists. "Who judges that they are terrorists?" asks Ron Paul, correctly.

Rick Santorum just accused Ron Paul of "seeing the world like Barack Obama does". No one has ever accused Ron Paul of that before. There are lies told by politicians – and then there's stuff like that, which is so wrong that it isn't even wrong, if that makes sense.

"When Rick Santorum is president," says Santorum, refering to himself in the third person – always a dangerous idea – Iran will never get nuclear weapons. Ron Paul returns to the attack, saying: "You've heard the war propaganda ... [but] Iran can't even make enough gasoline."

Oh an ad break. It's been very hard to keep up with all the back and forth, but this debate is much more fun.

For some reason Romney hasn't been asked a question for a while. He must have enjoyed seeing Pawlenty, Bachmann, Paul and Santorum beat the crap out of one another.

So now we get on to social issues. That should be nice and quiet.

Gingrich has been asked why he compared Muslims to Nazis. He doesn't bite this time but instead is going on about Communist spies. Has anyone told him about the whole Berlin Wall thing?

Herman Cain is trying to explain why he said something stupid about Mitt Romney's Mormonism. His explanation is a mysterious thing and leaves everyone no better off.

Ow. Bachmann is asked: "As President of the United States, would you be submissive to your husband?" As they say on the internet: WTF?

(There's a background to that question but it doesn't change the stupidity of it, frankly.)

Bachmann handles it very coolly, mentioning how long she's been married and how being "submissive" was about respect.

Jon Huntsman really looks like he's in pain. Perhaps he wishes he'd stayed in China.

He does however stick up for civil unions, which is brave.

Ron Paul is back and he's asked about marriage. He's against it, in the sense of: "Why should the government give a licence to get married?"

Rick Santorum accuses Paul of allowing polygamy or gay marriage on that basis.

Bachmann says she has "an unrivalled record when it comes to man-woman marriage". Supporting it, she means. Presumably.

That was the dullest part of any Republican debate: abortion. Because they all say the same thing.

Back to the economy! And Romney, who is doing the Hillary Clinton thing of pretending the others don't exist and is instead debating with the occupant of the White House.

Look how well that turned out for Hillary Clinton, eh?

@RickPerryFacts:

In Texas, a government shutdown happens anytime Rick Perry goes to sleep.

Ha! Jon Huntsman just refered, with a straight face, to "the EPA's reign of terror".

Huntsman's talking about his private sector experience at something called the Huntsman Corporation. He worked his way up from the bottom for a couple of weeks.

(Fact-ette: Huntsman Corporation makes those clamshell packages that hamburgers are served in.)

Michele Bachmann – winning a prize for chutzpah – says her vote against raising the debt ceiling was vindicated by S&P downgrading America's credit rating. Ahhh. Which is nuts because S&P downgraded the credit rating precisely because politicians like Bachmann were insane enough to vote against raising the debt ceiling.

Give Michele Bachmann lemons and she makes kool-aid.

Newt Gingrich is getting increasingly tedious. He stitches together various words and phrases until he thinks they sound important, then he stops, as if he's made a point.

Ad break! And, believe it or not, the ads are crazier than the candidates. One just attacked Nancy Pelosi over healthcare reform. That's very 2009.

Now Huntsman is saying he backed the debt ceiling deal passed by Congress.

"I think Speaker Boehner should be complimented for what he did, this nation should never default," he says. And quite right too – the default part – but it is hard to believe that he is the only one here who actually wanted to do the right thing and raise the debt ceiling.

That alone tells you some thing scary. Huntsman's current poll ratings are about 2%.

Now the candidates are getting a free and tedious summation. Santorum says he is the only candidate to have beaten three Democratic incumbents. But fails to mention that he got beaten like a gong by a Democrat last time up. Whoops!

Romney: blah blah blah jobs.

Gingrich tells people to call their congressmen (men?) "now" (at 11pm?) and tell them to "repeal Sarbanes-Oxley". Oh yeah that'll do it – mentioning 10-year-old legislation that most voters have never heard of.

That's it, finally. In a chilling move, Fox News flash up a little sign at the bottom of the screen: "Tomorrow: Sarah Palin."

OK then: first impressions. Well, Romney got away without a glove being laid on him and so everyone will say he "won" the debate on that basis, that he looked "presidential". I gave up counting how many debates Hillary Clinton "won" on that basis.

Because of the centrality of debates in these primaries, candidates really have to use them to move the ball down the field, as they say in America. Romney didn't: he played defence.

Gingrich was feisty and that may have gone down well but the other candidates ignored him so he had the luxury of talking to himself. His public persona remains unlikeable.

The crucial debate-within-a-debate was between Bachmann, Pawlenty and Paul, for the Iowa straw poll on Saturday, and Bachmann crushed Pawlenty's chances tonight – so she was the real winner in the debate overall.

As for Ron Paul, he may have rallied enough voters to make it a contest in the straw poll. But outside Ames he's simply too far off on the fringe of the party to be a contender.

More later.

Oh dear, "progressive" journalists trying to defend the "submission" question to Bachmann as not being sexist. Uh.

Local newspaper the New York Times has slapped together a few bits and pieces on the debates, probably using an intern.

And is it just me or is Mitt Romney looking and sounding more and more like John Kerry? Maybe it's the hair. And the wealth. And the being from Massachusetts.

Looking back through some clips, there's Romney saying: "Marriage is a status, it's not an activity." Who says romance is dead, eh?

Calling marriage a "status" makes it sound like a Facebook update.

In summary: The simplistic answer to the simplistic question of who won the debate is: Rick Perry. But that's not just simplistic, it's silly. You can't win a debate you're not in and it's not like his leading rivals (Romney, Bachmann) did great damage to themselves in the eyes of Republican primary voters. Bachmann may have disposed of Pawlenty in the Iowa straw poll, which would be a great result for her.

The thing is, would Perry have done any better? Given the format it's hard to say he would have. I'm sure he was happy not to be in the debate, but there were eight people on the stage, and with Perry there will be nine (assuming nothing changes) at the next debate in Tampa on 12 September. Nine candidates, two hours for a debate – the mathematics suggest that each candidate only gets three decent questions and a few shorter follow-ups. That doesn't leave any room for an actual debate, as we saw in 2007 in the early stages.

So while Perry and his team may have been happy to sit this one out, they will be faced with the prospect of having to take part next time. Until the field gets winnowed down, it's very difficult for any candidate to have much of an impact in debate answers alone.

In fact it's hard to say that debates like this make any real impression on voters, other than name recognition and the possibility of self-destruction. The real action is elsewhere at this point: fundraising, mainly, and Mitt Romney has being doing a lot of that recently.

If there wasn't a winner then there was certainly a loser: Tim Pawlenty. Two poor debate performances add up to a dismal showing, especially with rock-bottom poll ratings. Barring a miracle at the straw poll, he may as well throw in the towel.

Jon Huntsman angled for the moderate wing of the Republican party, backing civil unions and a sensible approach to the debt ceiling, in line with Congressional Republicans. That's pretty brave, in the climate of the current GOP and its "red lines". Much good it will do him. Maybe he is really running for 2016 – although for which party it's not entirely clear.

Otherwise it was certainly an improvement on the inane CNN debate in June, and Fox News has licence to go for Republicans in a way that other networks would be afraid of. The questions, while entertaining, were far too narrow and so meant it was hard to compare candidates' views on more general subject. The net result was we didn't learn much, other than the minutae of voting for Minnesota's cigarette tax increase.

Santorum, Cain and Gingrich just took up space. If they didn't get a spot on the platform in Tampa it would be an all-round gain.

My colleague Ewen Macaskill has filed his report on the debate:

Pawlenty badly needs to revive his campaign by doing well in the Iowa straw poll on Saturday, a traditonal test of would-be presidential candidates. If he fails, he could see his remaining financial backers desert him. Under pressure, his main target was predictably Bachmann, winner of the previous debate in New Hampshire and who is leading in the polls in Iowa. Adopting a patronising tone, he said Bachmann had done little in her five years in Congress. "She has done some wonderful things in her life but it is an indisputable fact that her record of accomplishment and results is nonexistent," Pawlenty said, trying to compensate for his failure to make an impact in the New Hampshire debate and shed his image of dullness. But he picked on the wrong candidate. Bachmann came back recalling his record in office as governor on health, energy and trade. "That sounds a lot more like Barack Obama's record," she said. She also raised his record on abortion, a litmus issue for Republicans.

Thanks for reading, we can do it all again on 12 September. Woo.

A final thought via the @RickPerryFacts Twitter feed: