Gerald Herbert, Associated Press
WASHINGTON — Mitt Romney swept to victory in the Arizona primary and led Rick Santorum in a close, hard-ought contest in Michigan Tuesday night, bidding for a two-state sweep and fresh momentum in the race for the Republican presidential nomination.
Two other candidates, Newt Gingrich and Ron Paul, made little effort in either state, pointing instead to next week's 10-state collection of Super Tuesday primaries and caucuses.
Romney's Arizona triumph came in a race that was scarcely contested, and he pocketed all of the 29 Republican National Convention delegates at stake.
Michigan was as different as could be — a hard-fought and expensive race in Romney's home state that he could ill afford to lose and Santorum made every effort to win.
Returns from 30 percent of Michigan's precincts showed Romney at 41 percent and Santorum at 38 percent. Paul was winning 12 percent of the vote to 7 percent for Gingrich.
In interviews as they left their polling places, Michigan voters expressed a notable lack of enthusiasm about their choices. Just 45 percent said they strongly favored the candidate they voted for, while 38 percent expressed reservations and 15 percent said they made the choice they did because they disliked the alternatives.
The lengthening GOP nomination struggle has coincided with a rise in Democratic President Barack Obama's prospects for a new term. A survey released during the day showed consumer confidence at the highest level in a year, and other polls show an increase in Americans saying they believe the country is on the right track.
Exit polling showed a plurality of Republican voters in both Michigan and Arizona saying the most important factor to them in the primaries was that a candidate be able to beat Obama in November. Romney won that group in Michigan, where it mattered most, and also prevailed among voters in the state who said experience was the quality that mattered most.
Santorum ran particularly well among voters who cited a desire for strong conservatism or strong moral character.
The polls surveyed both primary day and absentee or early voters. Interviews were conducted at 30 polling places in each state. Early results from Arizona's poll included interviews with 1,617 voters, including 601 absentee or early voters interviewed by phone. In Michigan it was 2,133 interviews including 412 absentee or early voters interviewed by telephone. The margin of sampling error for both polls was plus or minus 4 percentage points.
Not even the opening of polls on Tuesday brought an end to the squabbling between the two leading Republicans.
Romney accused Santorum of trying to hijack a victory in Michigan by courting Democratic votes through automated telephone calls and suggested his rival was appealing to conservatives by making the kind of "incendiary" statements he would not.
"I'm not willing to light my hair on fire to try and get support," Romney said. "I am what I am."
Santorum brushed aside the allegations of hijacking, saying Romney had appealed for support from independents in earlier states.
"We're going to get voters that we need to be able to win this election. And we're going to do that here in Michigan today," Santorum said, referring to blue collar voters with a history of swinging between the parties.
The exit poll said about 10 percent of the day's Michigan primary voters were Democrats.
If nothing else, the unexpected clash on Romney's home field dramatized that two months into the campaign season — after nearly a dozen primaries and caucuses — the GOP race to pick an opponent for President Barack Obama remains unpredictable.