The leading Republican presidential candidates scrambled to take command of a new landscape on Sunday after Tim Pawlenty abruptly ended his campaign and a three-way race began taking shape to find a nominee who can emerge as the strongest challenger to President Obama.
While Gov. Rick Perry of Texas had hoped to turn the contest into a two-man duel with Mitt Romney, he starts by facing Representative Michele Bachmann, whose weekend victory in the Iowa straw poll reordered the top tier of candidates. On the second day of his announcement tour, Mr. Perry sent a subtle message: making his first Iowa appearance in her hometown, but not taking her on directly.
While Mrs. Bachmann, Mr. Perry and Mr. Romney each have emphasized cutting attacks on Mr. Obama, they now face the need to begin drawing distinctions with one another and set up what could be a long and hard-edged campaign for the party’s nomination.
Their pitches often overlap, with Mr. Perry and Mr. Romney presenting themselves as job creators, while Mr. Perry and Mrs. Bachmann appeal to social conservatives.
The contrasts are becoming increasingly clear as the slow-to-start campaign accelerates and candidates prepare to participate in three debates next month alone.
Mr. Obama is also stepping up his campaign. He will begin a three-day bus tour of the Midwest on Monday with appearances in Minnesota and Iowa, swooping into a region that is vital to his re-election to make a case that he has stabilized the economy and has the right prescriptions for continued improvement.
But as Republican optimism rises at the possibility of defeating Mr. Obama, a new air of urgency has gripped the nomination fight, with early strategies beginning to take shape.
Mrs. Bachmann is counting on a strong showing in the Iowa caucuses early in the new year. Mr. Romney is investing heavily in New Hampshire. Mr. Perry said he would not focus on a narrow strategy and pledged to compete in all corners of the country by emphasizing economic issues and his record of promoting job creation over the past decade in Texas.
“At the end of the day,” Mr. Perry told supporters here, “getting America working again is what the bulk of the people really care about.”
Mr. Romney appeared at a private fund-raiser in Nantucket, Mass., on Sunday and held no public campaign events. But in New Hampshire on Monday, aides said, he will continue his focus on the president and criticize his bus tour, avoiding becoming dragged into the back-and-forth of the Republican nominating contest until he has to.
Mrs. Bachmann, whose straw poll victory led Mr. Pawlenty to drop out of the race and solidified her role as a leading contender here in Iowa, is seeking to expand her appeal and win over voters who admire her passion but remain unsure of her level of experience. She appeared on all five Sunday morning talk shows, peppered with questions about her opposition to raising the debt ceiling, her views about gays and lesbians and the role that faith would play in a Bachmann administration.
“All of these kind of questions aren’t what people are concerned about right now,” Mrs. Bachmann said on the NBC program “Meet the Press.” But pressed on the issues, she said, “I think my views are clear.”
Mr. Pawlenty’s abrupt departure from the race, after finishing a distant third in the straw poll, created one of the most significant ripples yet in the Republican nominating fight. While he struggled to generate the enthusiasm of Mrs. Bachmann’s backers, he had a core group of loyal fund-raisers and supporters from Iowa to Florida that rival campaigns immediately started to pursue.
He said that he had no immediate plans to endorse another candidate.
Ray Washburne, a Dallas businessman and a top bundler for Mr. Pawlenty, said he received telephone calls from Mr. Romney and Mr. Perry on Sunday morning not long after Mr. Pawlenty announced his intention to leave the race. Both campaigns were aggressively pursuing political operatives, contributors and rank-and-file supporters.
“When the girlfriend breaks up with you,” Mr. Washburne said, “you’re not ready to start dating just yet.”
Mrs. Bachmann’s candidacy, which has rapidly gained visibility and credibility since she joined the race two months ago, has tapped into a sense of anger and frustration that voters have with Washington. Her engaging speaking style, personal connection with voters and appeal to conservative activists contributed to her victory at the straw poll on Saturday.
It remains an open question whether she can tap into the economic message that rival Republicans are building their candidacies around. But she signaled on Sunday that she has no intention of ceding the ground she has built in Iowa. When Mr. Perry made plans to hold his first Iowa appearance in her childhood hometown, Waterloo, she said she would join him.
The setting of their first meeting was the Electric Park Ballroom on the grounds of the National Cattle Congress in Waterloo, the same place Mrs. Bachmann held a rally on the eve of her announcement in June. As he entered the room, Mr. Perry declared: “Man, y’all got a crowd here; this is awesome.”
“You’d think you were in Texas if you didn’t know better,” Mr. Perry said.
Mrs. Bachmann stayed on her campaign bus until Mr. Perry had finished speaking. She made no acknowledgment of her rival even as he sat at a dinner table just feet from where she stood. Mr. Perry applauded politely when Mrs. Bachmann criticized the president, but otherwise sat quietly during her speech.
Ed Rollins, the campaign manager for Mrs. Bachmann, said after the event that “the debate will be there” soon enough.
“We’ve got three to four debates in September,” he said. “We will all be on the same stage, and everybody gets to make their judgments.”
Mr. Perry’s entrance is not likely to alter Mr. Romney’s strategy, at least in the short term. Senior aides to Mr. Romney have long believed that they would face a social conservative who would emerge out of Iowa. The Romney campaign may be content to watch Mr. Perry and Mrs. Bachmann clash, but are waiting to see how Mr. Perry develops as a candidate before deciding their approach.
If Mrs. Bachmann emerges from that clash early next year in a stronger position than Mr. Perry, the contrast with Mr. Romney would be particularly sharp. But if Mr. Perry were to prevail, Mr. Romney is positioned to make the case that his experience in the private sector — a businessman and the savior of the 2002 Winter Olympics in Utah — trumps years as a politician in Texas.
For now, the campaign is unfolding as a Romney-Perry-Bachmann competition. But Jon M. Huntsman Jr., a former governor of Utah and ambassador to China, is steadily raising criticism of Mr. Romney, reflecting his strategy of positioning himself as an alternative to Mr. Romney in New Hampshire. Representative Ron Paul of Texas, who finished a close second in the straw poll, could also influence the race with his strain of libertarian views that have become more popular in this economic climate.
“This is a very fluid situation right now,” Senator Charles E. Grassley, Republican of Iowa, said as he arrived at the Waterloo event on Sunday evening, the day after the straw poll delivered the first significant organizing test of the campaign. “From here on, you are shooting with real bullets.”
Jeff Zeleny reported from Des Moines, and Michael D. Shear from Waterloo.
This story, "," originally appeared in The New York Times.