WASHINGTON – Barack Obama and Hillary Rodham Clinton squared off in a scrappy Wisconsin primary and in laid-back Hawaii caucuses Tuesday, their struggle for the Democratic presidential nomination veering toward the negative.

Wisconsin offered 74 national convention delegates, and an early test of support in industrial states such as Ohio and Pennsylvania.

There were 20 delegates at stake in Hawaii, where neither Clinton nor Obama campaigned in person.

Obama began the night with 1,281 delegates in The Associated Press count, and Clinton with 1,218. It takes 2,025 to win the nomination at the party’s national convention in Denver.

Independents cast about one-quarter of the ballots in the Wisconsin race between Obama and Clinton, and roughly 15 percent of the electorate were first-time voters, according to preliminary results from interviews at polling places. Obama has run well among independents in earlier primaries.

The economy, and trade in particular, was a key issue, according to the survey. Seven in 10 Democratic primary voters said U.S. trade with other countries winds up costing jobs in Wisconsin. Fewer than one in five said it creates more jobs than it loses.

Republican front-runner John McCain hoped to inch closer to wrapping up the GOP nomination in primaries in Wisconsin and Washington, with 56 delegates at stake. The Arizona senator had 908 delegates, and his closest remaining rival, former Arkansas Gov. Mike Huckabee, had 245. Texas Rep. Ron Paul had 14.

Obama began the evening with eight straight primary and caucus victories, a run that has propelled him past Clinton in the overall delegate race and enabled him to chip away at her advantage among elected officials within the party.

Clinton’s aides initially signaled she would virtually concede Wisconsin, and the former first lady spent less time in the state than Obama.

Even so, she ran a television ad that accused her rival of ducking a debate in the state and added that she had the only health care plan that covers all Americans and the only economic plan to stop home foreclosures. “Maybe he’d prefer to give speeches than have to answer questions” the commercial said.

Obama countered with an ad of his own, saying his health care plan would cover more people.

In San Antonio on Tuesday, Obama said her idea to freeze the monthly rate on adjustable rate mortgages for at least five years would raise rates on new mortgages. “Even more families could face foreclosure,” he said. “That’s why one economic analyst called her plan disastrous.”