JIM LEHRER: And to the 2012 presidential campaign.
Gwen Ifill begins our coverage.
MAN: That's the best thing at the fair.
MITT ROMNEY, (R) presidential candidate: Is that the best thing at the fair?
GWEN IFILL: They're all here, deep into an Iowa summer, as the 2012 presidential campaign suddenly picks up speed.
Former Mass. Gov. Mitt Romney tackled hecklers at the state fair.
MITT ROMNEY: Hold on just a moment. Hold on just a moment.
You know what? I get a chance -- I'm going to let you speak in a moment.
MAN: You came here to...
MITT ROMNEY: You ready for my answer? I'm not going to raise taxes. That's my answer. I'm not going to raise taxes.
(CHEERING AND APPLAUSE)
MITT ROMNEY: And if you want somebody that is going to raise taxes, you can vote for Barack Obama. But let me tell you what Barack Obama is doing. Barack Obama is killing this economy.
GWEN IFILL: Minn. Rep. Michele Bachmann targeted her appeal to the state's powerful network of social conservatives.
REP. MICHELE BACHMANN, R-Minn. presidential candidate: It's about having somebody who's new and bold and different and somebody who is going to go in and get her done. I'm not interested in two terms or not. I'm interested in getting it done this time. We got to get it right in 2012.
(CHEERING AND APPLAUSE)
REP. MICHELE BACHMANN: We are going to have a tidal wave election. With the right candidate, it will be a tidal wave.
GWEN IFILL: As political spectacles go, it was hard to look away. The candidates flocked to the famous state fair, with its fried food, amusement rides, its cow carved out of butter and its potential voters.
BOB KELLY, Iowa: People are really fed up with Congress, no matter what party. I think it's down to 10 percent approval. So something's got to change.
GWEN IFILL: Add to that last night's candidates debate, where the two Minnesotans, former Gov. Tim Pawlenty and Bachmann, took aim at one another.
REP. MICHELE BACHMANN: I have a very consistent record of fighting very hard against Barack Obama and his unconstitutional measures in congress. I'm very proud of that record. That is what qualifies me, as a fighter and representative of the people, to go to Washington, D.C. and to the White House.
TIM PAWLENTY, (R) presidential candidate: She led the effort against Obamacare, we got Obamacare. She led the effort against TARP, we got TARP. She said she's got a titanium spine. It's not her spine we're worried about. It's her record of results.
If that's your view of effective leadership with results, please stop, because you're killing us.
GWEN IFILL: Other candidates just fought to be taken seriously.
RICK SANTORUM, (R) presidential candidate: You need leaders. You need people who are good at leadership, not showmanship.
CHRIS WALLACE, "Fox News Sunday": How do you respond to people who say that your campaign has been a mess so far?
NEWT GINGRICH, (R) presidential candidate: Well, let me say, first of all, Chris, that I took seriously Bret's injunction to put aside the talking points, and I wish you would put aside the gotcha questions.
(CHEERING AND APPLAUSE)
SUSAN FERRECHIO, Washington Examiner: When President Obama joked about protecting the borders with alligators and a moat, not only did you embrace the idea, you upped the ante with -- quote -- "a 20-foot barbed wire electrified fence."
Were you serious?
HERMAN CAIN, (R) presidential candidate: America -- America has got to learn how to take a joke.
GWEN IFILL: The Des Moines Register's Kathie Obradovich says Saturday's big Straw Poll in Ames, part street fair, part hardball political exercise, will be the biggest candidates test so far.
KATHIE OBRADOVICH, The Des Moines Register: Historically, the Straw Poll has not really been important by itself. It's just a party fund-raiser. Candidates have caught on to the fact that the media pays a lot of attention to this.
And so they started back in the '80s really organizing heavily to try to get people to the Straw Poll, so that they would show themselves to be ahead of the pack. Well, what has happened over the years now is that it has become seen as a real test of candidates' strength and the organizational muscle that they have. And that's important for the caucuses.
GWEN IFILL: The three events are a political trifecta, but the announced candidates now risk being upstaged by two candidates not yet in the race: Texas Gov. Rick Perry, who travels to New Hampshire, South Carolina, and Bachmann's Waterloo, Iowa, birthplace this weekend to announce his entry into the race.
KATHIE OBRADOVICH: He could actually steal headlines away from candidates who have really worked here for a year leading up to this day.
GWEN IFILL: And 2008 vice presidential nominee Sarah Palin, who arrived to work the state fair today.
Doug Gross chaired Romney's state campaign four years ago.
DOUG GROSS, Republican Party activist: Stalwart Republicans. Those are the Republicans that are not focused solely on social issues, but are focused on economic issues and a desire to beat Obama. Lots of those folks, like myself, are unaffiliated. We haven't decided who we're going to support. So, frankly for both of them, there's still plenty of time.
GWEN IFILL: Iowa has served as the political launching pad, or graveyard, for presidential candidates since 1976. That's when Democrat Jimmy Carter came out of nowhere to win the January caucuses.
So, although candidates like Romney and former Utah Gov. Jon Huntsman won't take part in tomorrow's Straw Poll, all made sure they were on stage for last night's FOX News candidates debate.
JON HUNTSMAN, (R) presidential candidate: We were the best-managed state in the country. We maintained a AAA bond rating -- all of the things this country so desperately needs.
When you look at me and you ask, what is that guy going to do, look at what I did as governor. That is exactly what I'm going to do, and it's exactly what this country needs right now.
(CHEERING AND APPLAUSE)
GWEN IFILL: All of the candidates are hoping to harness the previously unmeasured power of the state's Tea Party movement.
RYAN RHODES, Tea Party activist: Hey. How you doing?
GWEN IFILL: Ryan Rhodes, who has been organizing Tea Party voters in Iowa, has decided to back Bachmann.
RYAN RHODES: I think there's a lot of people that are looking for someone to be that strong candidate, to step forward and articulate what they're saying.
Right now, these people have to be -- have to go beyond just the grassroots activists, because, right now, the only people paying attention are the really, really kind of avid political people, like you and me and things like that. The average Iowan isn't paying that much attention. The average American is not paying -- because they're working too hard to try to pay their bills.
GWEN IFILL: Indeed, with all the political activity now under way, even some of the most activists themselves remain undecided.
DOUG GROSS: Like myself, I haven't made up my mind. Here I am, I have been involved in these things for Republican politics since 1988. I want to have a candidate who has a winning message. I absolutely believe a winning message has to focus on the economic troubles facing our country that we read about and live every day.
Right now, a lot of our candidates are not talking about things we really care about. And that's those issues. I'm going to wait and see who can do the best job at that.
GWEN IFILL: Less engaged voters only know they want someone, anyone, who can beat President Obama.
JOSHUA BIERBAUM, Iowa: There's quite a few candidates out in the field. I don't really see any front-runner right now, other than Mitt Romney, who hasn't shown that he's very interested in the state of Iowa right now.
MARY LOU CUBIT, Iowa: I think that Obama has failed to show his leadership ability, and I'm anxious to have somebody replace him.
GWEN IFILL: Every candidate is hoping to capitalize on that unhappiness.
MAN: And if you can come to Ames this Saturday, cast a ballot for me and my campaign, I would really appreciate it.
REP. RON PAUL, R-Texas presidential candidate: I do know that you can make the difference. And one vote in a straw vote in a situation like this is very, very valuable. It gets national attention. So, what happens on Saturday can really give us a boost.
REP. MICHELE BACHMANN: I love you. See you on Saturday.
GWEN IFILL: Let the games begin.
REP. MICHELE BACHMANN: We will see you there. I'm going to be looking for you. Bye!