The last time Michigan had a competitive Republican presidential primary, in 2000, self-described Republican voters were a minority. Tuesday's GOP primary had a much more normal partisan split, with a solid majority of Republicans and far fewer Democrats.

Michigan has open primaries and no registration by party, so voters choose on primary day which partisan contest to vote in. In 2000 with no Democratic race but for an eventual blowout in caucuses three weeks later, many Democrats voted in the Republican primary -- totaling 17 percent of that electorate, more than in any other GOP primary exit poll since at least 1992.

On Tuesday there were both Democratic and Republican primaries and though ballot maneuvering left the Democratic side in essence non-competitive, apparently it kept some Democrats from migrating to the Republican contest -- where they made up fewer than one in 10 voters. In 2000, Republicans made up only 48 percent of the GOP primary electorate; Tuesday they were two-thirds of it. A quarter of Republican primary voters Tuesday called themselves independent, down from 35 percent eight years ago.

In all, the exit poll indicated seven in 10 voters Tuesday opted to vote in the Republican primary. Among those who did vote on the Democratic side, more than three in four called themselves Democrats.

It's the economy ... at least in Michigan

Given four choices, half of Michigan Republican primary voters picked the economy as the most important issue facing the nation -- compared to just 26 percent in the Iowa GOP caucuses and 31 percent in the New Hampshire Republican primary. Its auto industry ailing, Michigan has the highest unemployment rate in the nation. Among the other choices, one in five picked Iraq, one in seven said immigration and one in 10 called terrorism the country's most important issue.

On a different question, only three in 10 Michigan GOP voters rated the nation's economy excellent or good, compared to half of Republican primary voters in New Hampshire.

On other issues ...

Among Michigan Republican primary voters:

• Six in 10 say abortion should be illegal in most or all cases

• A similar number approve of the war in Iraq

• A little more than half say it should be higher priority for the next president to reduce the budget deficit rather than cut taxes

That Democratic non-contest ...

Barack Obama and John Edwards withdrew from the ballot amid a dispute over seating Michigan's Democratic delegates. "Uncommitted" was an option on the ballot against Hillary Rodham Clinton and several lower-tier candidates. Younger voters, college graduates, blacks and voters in bigger cities were more likely than other groups to vote uncommitted.

And if Democrats had a full ballot to choose from, nearly three-quarters of those who voted uncommitted told exit pollsters they would have voted for Obama and many of the rest said Edwards. Of course those results are only among those who were motivated to go to the Democratic primary and vote uncommitted.

Note:Preliminary results from exit poll by Edison Media Research and Mitofsky International for The Associated Press and television networks. Partial samples in 40 precincts around Michigan of 873 voters in the Republican primary and 588 in the Democratic contest. Sampling error plus or minus 5 percentage points in each primary.