GRAND RAPIDS, Mich. — Bested by Mitt Romney in Arizona and Michigan, Rick Santorum vowed on Tuesday night to continue fighting for the Republican presidential nomination and claimed partial victory by wounding his rival with Super Tuesday just a week away.
"A month ago they didn't know who we are, but they do now," Santorum told supporters gathered in a downtown hotel. "We came into the backyard of one of my opponents, in a race that everyone said, 'Well, just ignore, you have really no chance here.' And the people of Michigan looked into the hearts of the candidates, and all I have to say is: I love you back."
Santorum's advisers noted that Santorum and Romney essentially split the delegates in the Michigan contest because of new party rules, regardless of what the popular vote may have been. Senior strategist John Brabender and others suggested Romney would emerge from Michigan as a weaker candidate.
"God bless him for spending a fabulous amount of money to come into his home state to eke out a victory in the total count and to walk away with many fewer delegates than anybody thought humanly possible two weeks ago," Brabender said.
Santorum's second-place finish follows a distinctly negative shift in the Republican presidential race that has some GOP officials worried about the party's prospects against President Barack Obama in November.
In the hours before the Michigan results were finalized, Santorum and Romney sparred via media reports from opposite ends of the state.
Santorum declared himself a conservative "heavyweight," while defending his decision to court Michigan Democrats in the state's high-stakes GOP primary.
Romney "is a lightweight on conservative accomplishments, which happens to be more important than how much success and how much money you've made in business," Santorum told reporters while visiting a campaign call center in this western Michigan city.
Earlier in the day, Romney had fueled the intensifying war of words by calling Santorum "an economic lightweight."
Romney cruised to victory in an Arizona primary that Santorum and the other Republican candidates — Newt Gingrich and Ron Paul — did not actively contest.
The focus fell largely on the Michigan primary because of Romney's struggle here, despite several natural advantages. He was born and raised in Michigan and his father served as the state's governor in the 1960s.
The Michigan contest took an unusual turn on the eve of the election when Santorum's campaign used automated telephone calls to encourage Democrats to vote against Romney.
Romney complained that the tactic was "deceptive and a dirty trick."
Santorum, a former Pennsylvania senator, suggested that Romney did much the same thing when he courted independent voters in New Hampshire's GOP primary last month.
Santorum's appeal to Democrats may have helped.
Nine percent of voters in Michigan said they were Democrats, according to exit polling. Santorum carried 53 percent compared with 18 percent for Romney and 17 percent for Paul.
Only Michigan Republicans were allowed to vote in Tuesday's GOP primary, but party rules also allow voters to change their affiliation temporarily on the spot.
Santorum's automated message said Democrats should send "a loud message" to Romney by voting for Santorum. Romney said the tactic was "a new low" in the campaign.
Santorum's strategy was predicated on building an unlikely coalition of Democrats, tea party activists and religious conservatives. He spent the final day of campaigning with his wife, Karen, in Grand Rapids, a city set in a western Michigan region home to many of his party's more conservative voters.
Santorum's recent rise to prominence in the GOP presidential contest has been fueled by a continued reluctance among the GOP's more conservative voters to embrace Romney.
"I don't trust him," Carol Alexander, of nearby Wyoming, Mich., said of Romney while waiting for Santorum to arrive at the Rainbow Grille in Grandville, Mich.
A self-described religious conservative, she said she was leaning toward Santorum, who she says "speaks what he believes."
Alexander said she's been inundated with phone calls from campaigns, adding that "it's been getting kind of nasty." But she discounted the impact of Santorum's latest tactic.
"Do you really think a liberal is going to vote for Santorum?" she asked with a smile. "I don't think they're going to do it."