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Donald Trump goes to war with Iowa's top pollster

Republican presidential candidate is quick to tell the world when a new poll shows him in first place. But he's also quick to point out when he doesn't like the results. Just minutes before the release of the newest Des Moines Register - which showed rival Texas Sen. Ted Cruz in first place with a 10-point lead, he took to Twitter to inform people it couldn't be trusted.

Typos aside - it appears Trump meant to write that the Des Moines Register's poll was biased against him, not toward him. His campaign manager doubled down, telling the Washington Examiner, that the Register "is a biased media outlet and shouldn't be taken seriously. Their history of polling is rated the worst."

In fact, the Des Moines Register's longtime pollster, J. Ann Selzer, has a long history of being right about Iowa politics - especially when it comes to the caucuses.

Last presidential cycle, it was her poll just days before the caucus that showed former Pennsylvania Sen. Rick Santorum surging from single-digit support to what would ultimately become a first-place finish. In 2004, her poll correctly previewed the finishing order of the Democratic candidates: then-Sen. John Kerry, then-Sen. John Edwards, and then-Vermont Gov. Howard Dean. In 2008, Selzer's poll correctly captured the unprecedented increase in first-time caucus attendees that propelled then-Sen. Barack Obama to victory over then-Sen. Hillary Clinton.

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Clinton and Edwards, whose campaigns both slammed that poll, found out the hard way that Selzer was right when they lost to Obama that cold January night.

"We certainly have a track record of getting this right when other polls didn't," Selzer told CBS News. Her methodology is to "cast a wide net" for poll respondents, which is more expensive but also effective: She can identify the universe of people likely to participate in caucuses regardless of whether they've done it before.

"Ann Selzer's certainly very respected here in state and beyond because she's so good at what she does," Iowa political operative Eric Woolson told CBS News. "I don't know that your average Iowan would get their dander up and go, 'Oh my gosh, Trump's attacking her,' but I think folks involved in the process will know he's angry because her numbers are right. To me it's a classic case of kill the messenger."

Trump has been careful to focus his attacks on the Des Moines Register specifically. There's no love lost between him and the paper, which said in a July editorial that he should quit the presidential race.

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"In a sense it's smarter for him to go after the Register rather than Selzer herself," University of Iowa political science professor Timothy Hagle told CBS News. Craig Robinson, editor of The Iowa Republican, confirmed: "In Iowa, amongst Republican activists, beating up on the Des Moines Register isn't necessarily an unpopular thing to do. I just think this is kind of his way of dealing with a poll that shows him in second place."

After a CBS News/New York Times poll in October showed him trailing Ben Carson nationally, Trump simply denied the accuracy of the poll. "I think I'm winning in Iowa," he said. "I don't believe I did fall behind," he said a town hall hosted by NBC's "Today" show.

Hagle noted that Trump has a history of going on the offensive, pointing to his treatment of Fox News' Megyn Kelly after she asked him about his inflammatory statements about women during a debate.

"You have to wonder whether that strategy is going to ultimately fail," Hagle said. So far, it hasn't. As Republican consultant and CBS News contributor Frank Luntz found in a focus group earlier this week, Trump supporters tend to find a way to justify his attacks even if they don't like what he said.

Woolson said he expects Trump's supporters will brush off the poll as evidence of media bias. He speculated that perhaps the attacks help motivate his campaign team.

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"Every outrageous thing he says seems to work, whereas picking a fight with the Iowa poll and the Register may not work for a lot of candidates it may be just smart thing for him," Woolson said.

Selzer herself isn't bothered by the outburst.

"Donald Trump seems to think that somebody like me would have a reason to want to intentionally bias a poll and I can't think of one. I can't think of any upside to wanting to do that," she said. "He didn't' say that when he was leading in our poll in August and my feelings are unchanged. He needs to say something. I don't take it very seriously."

But she is also quick to point out that this is just the latest poll -- it will not be the last. In the days before voters head to their local schools and churches to caucus, the results can change dramatically, as they did in Iowa in 2012.

An earlier version of this article incorrectly stated that Timothy Hagle teaches at Drake University. He teaches at the University of Iowa.

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