INDIANAPOLIS | A public opinion poll released Monday found Democrat Joe Donnelly leading Republican Richard Mourdock in their race to become Indiana's next U.S. senator.

The Sept. 10-12 Global Strategy Group survey of 800 likely Hoosier voters found 45 percent favoring Donnelly versus 42 percent supporting Mourdock.

The poll, which was sponsored by the Donnelly campaign, has a margin of error of plus or minus 3.5 percent, meaning Donnelly and Mourdock remain statistically tied. Every poll in the race since Mourdock defeated U.S. Sen. Dick Lugar in the May Republican primary has reported a dead heat.

That didn't stop Donnelly campaign manager Paul Tencher from cheering the latest results.

"The poll shows that despite Richard Mourdock's Wall Street allies spending nearly $1 million against Joe since the beginning of September, Hoosier voters are responding to his message of common sense and bipartisanship," Tencher said.

Mourdock faces an uphill climb to win the race. According to the poll, the remaining undecided voters are twice as likely to have an unfavorable view of Mourdock compared with Donnelly.

In the presidential contest, the poll found Republican Mitt Romney has a six-percentage-point lead over Democrat Barack Obama, 47-41, in Indiana.

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