COLUMBUS, Ohio (AP) _ Secretary of State Kenneth Blackwell won the GOP nomination for governor Tuesday after campaigning as the best candidate to deliver his party from a year of political scandals and infighting.

With more than half of precincts reporting, Blackwell had 257,531 votes, or 55 percent, compared with 208,481, or 45 percent, for Attorney General Jim Petro.

The gubernatorial primary was seen as a test of voter dissatisfaction that could foreshadow the party's prospects in November.

``The Republicans have a problem,'' said Carl Rullmann, a GOP voter who said he supported Blackwell.

Two other states also held primaries Tuesday, including North Carolina, where the district attorney prosecuting the Duke University rape case fought off two challengers, and Indiana, where congressional incumbents easily won their party nominations.

Blackwell's prominence as a leading black voice in the GOP could be pivotal to Republicans. He is the first black candidate to run for governor in Ohio. His ads sought to taint Petro with connections to the state's investment in rare coins that went awry and to tie him to Gov. Bob Taft, who pleaded no contest to four ethics violations last year involving a failure to report free golf outings and gifts.

Petro hammered Blackwell as a hypocrite who opposes abortion and gambling even though some of his multimillion-dollar stock portfolio is invested in those interests.

The GOP disunity may have turned off some voters.

``I saw a lot of backstabbing, name-calling, character assassination. I don't go for that kind of stuff,'' said James Martin, 66, leaving a polling place in the Cleveland suburb of Strongsville. He said the negative campaigning influenced his choice in the Republican primary, but he would not say who that was.

The Ohio scandals also emboldened Democrats who hope to end the Republicans' 15-year hold on the governor's office.

The winner of the primary will face Democratic U.S. Rep. Ted Strickland in November. Strickland is viewed as the Democrats' best chance to regain some control over a state government where Republicans control all three branches, as well as statewide offices and a majority of congressional seats.

Strickland handily defeated a former state legislator for the nomination. With 60 percent of precincts reporting, he had 331,823 votes, or 78 percent.

Republicans targeted the House seat Strickland leaves open as one of its best shots nationally to gain a Democratic congressional spot. They have been helped by the fact the Democrats' leading candidate must run as a write-in due to a filing mistake. National Democrats and Republicans have spent roughly $1 million in the race, more than they have for any primary in the past decade.

Ohio's U.S. Senate race will also be closely watched in the fall, but incumbent Sen. Mike DeWine and his Democratic rival, U.S. Rep. Sherrod Brown, easily emerged from the primary.

In North Carolina, the allegations against Duke athletes turned what might have been a low-key election into a referendum on Mike Nifong's performance.

In unofficial results, Nifong had 45 percent of the vote, with challenger Freda Black close behind with about 42 percent. There are no Republicans running in the general election, and Nifong needed only 40 percent of the vote to avoid a runoff.

In Indiana, all nine congressional incumbents advanced to the November election. Most challengers were short on money and party support. Sen. Richard Lugar, one of the most popular politicians in state history, had no Republican opposition.