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DES MOINES — Tim Pawlenty, the former governor of Minnesota, dropped his bid for the Republican nomination for president on Sunday morning, saying his disappointing performance in Iowa’s straw poll convinced him that his campaign had run its course.

Just hours after his third-place finish in Iowa, Mr. Pawlenty said on ABC’s “This Week” program that his message “didn’t get the kind of traction we needed and hoped for” in order to continue.

“There are a lot of other choices in the race,” he said. “The audience, so to speak, was looking for something different.”

Mr. Pawlenty informed his supporters on a conference call Sunday morning before his television appearance that he was ending his candidacy. He thanked his supporters in the call, two participants said, but acknowledged that he had decided overnight that his candidacy could not proceed.

Mr. Pawlenty, who had been weighing a presidential campaign for years, had developed a robust plan to win the Republican nomination. But his strategy did not take into account the rising popularity of a fellow Minnesotan, Representative Michele Bachmann, whose candidacy had overshadowed Mr. Pawlenty’s. He had staked his entire campaign around a strong finish at the Iowa straw poll, which he did not achieve.

Mrs. Bachmann won the poll, edging Representative Ron Paul of Texas. Mr. Pawlenty was a distant third.

It was a sudden end to the presidential candidacy of a former two-term governor, who had once talked about bypassing the straw poll. But a poor showing at a debate two months ago made him change his mind, associates said, and left him with no choice but to throw everything into the straw poll.

On “This Week,” Mr. Pawlenty said he would probably endorse one of his former rivals eventually, but he declined to do so Sunday morning. Asked what he thought of Mrs. Bachmann, Mr. Pawlenty said she would be “tested” through the nomination process.

“I think she’s qualified,” he said. “She’s going to have to make her case.”

Speaking moments later on the same program, Mrs. Bachmann praised Mr. Pawlenty, but she said that the message from her victory in the straw poll was that voters are looking for “someone authentic” like her.

“I’m talking about what people really care about,” she told Jake Tapper, the host of the ABC program. “You saw a big message sent to Washington. They really want someone they can trust and can believe in.”

Mr. Pawlenty first became a national figure four years ago as a finalist to be the vice presidential nominee for Senator John McCain of Arizona. That job eventually went to Sarah Palin, the governor from Alaska.

Four years later, Mr. Pawlenty became the first major Republican to announce a presidential bid. He quickly assembled a campaign staff that included top operatives and experienced donors. He began traveling to neighboring Iowa.

Asked whether he would consider being a vice presidential candidate in 2012, Mr. Pawlenty said he would not.

“I’ve been down that road before,” he said. “That’s not something I’m going to consider.”

In months of campaigning through Iowa, Mr. Pawlenty had presented himself as a can-do governor whose experience as the chief executive of Minnesota for eight years would make him a good president.

“We need somebody who is a tested, proven leader with results who can fix the country and get it back on track boldly and quickly. That’s what I did in Minnesota. That’s what I’ll do for the country,” he said during a stop recently in Grinnell, Iowa.

Mr. Pawlenty also increasingly took aim at President Obama, describing the state of the country in gloomy ways and blaming Mr. Obama for failing to do what was necessary to turn the nation’s economy around. He made that case in television ads, running four ads ahead of the straw poll and spending nearly $1 million.

But Mr. Pawlenty was seen as making his first big mistake during a debate in New Hampshire in June. After coining the term “Obamneycare” before the debate, he declined on the stage to go on the attack with his rival, Mitt Romney, standing on the stage.

That was viewed by donors and activists as a missed opportunity to stand up to his leading Republican rival. Raising money, which had always been hard for the campaign, became tougher after that.

The biggest challenge for Mr. Pawlenty came as Mrs. Bachmann’s campaign picked up steam. Mr. Pawlenty’s strategy had been built around a strong finish in Iowa, and the straw poll became a way to prove to reluctant donors and supporters that the strategy was still sound.

In the Fox debate on Thursday, two days before the straw poll, Mr. Pawlenty took direct aim at Mrs. Bachmann, hoping to dent her momentum in Iowa.

“Her record of accomplishment and results is nonexistent. That’s not going to be good enough,” he said during the debate. “The American people are going to expect more and demand more.”

But Mrs. Bachmann deftly handled the attacks, accusing Mr. Pawlenty of holding positions that sound “a lot more like Barack Obama, if you ask me.”

The exchange clearly benefited Mrs. Bachmann more than it did Mr. Pawlenty, who received less than half of her votes in the straw poll. In the end, Mr. Pawlenty concluded that he could not continue.

“It was disappointing,” he said. Asked about the candidates remaining, Mr. Pawlenty said: “They are going to be tested. As you know, it’s a big, bright light that comes down on you. And we’ll see.”