INDIANAPOLIS (AP) — U.S. Rep. Baron Hill endorsed Barack Obama on Wednesday, giving the presidential hopeful a potential boost going into Indiana's primary next week.

The southern Indiana congressman, who is a superdelegate to the Democratic National Convention, planned to publicly announce his decision during an Obama campaign rally Wednesday night at Indiana University's Assembly Hall in Bloomington, Hill spokeswoman Katie Moreau said.

Hill said in a statement that some had advised him to not choose yet between Obama and Hillary Rodham Clinton, but decided he could not wait.

"I believe Senator Obama has the capability to change the tone and tenor of politics in Washington," Hill said. "I believe that he can and will work with both parties and elevate the level of public discourse."

Clinton has won by large margins in other states in largely rural districts like the one Hill represents in southeastern Indiana. Obama, though, is expected to run well in Monroe County, which includes Bloomington and is the district's most-populous county.

Hill joins Rep. Andre Carson of Indianapolis in endorsing Obama. The state's three other Democratic congressmen have not backed either candidate, while Sen. Evan Bayh is supporting Clinton.

Hill has represented Indiana's 9th District for all but two years since 1998. He is expected to face Republican Mike Sodrel in the November election for the fourth consecutive time, with Sodrel winning in 2004 before Hill took the seat back in 2006.

Polls have shown a tight race between Clinton and Obama in Indiana as they seek the 72 pledged delegates at stake in Tuesday's primary.

The endorsement from Hill — a member of the Blue Dog Coalition, a group of fiscally conservative Democrats in Congress — gives Obama the backing of four Indiana superdelegates to five supporting Clinton. Those superdelegates are party leaders and elected officials who are free to vote as they choose at the Democratic convention.

Hill said he was satisfied with how Obama dealt this week with the troubles surrounding remarks by his former pastor, the Rev. Jeremiah Wright, and that it showed Obama was a leader.

"We cannot continue to pursue the same politics of personal destruction we have engaged in for a generation, some never-ending 'Groundhog Day' endlessly playing out the cultural wars of 40 years ago," Hill said.

Hill said he met with both Obama and Clinton and spoke with his predecessor in the House seat, Lee Hamilton, before deciding to support Obama. Hamilton, who endorsed Obama in early April, spent 34 years in Congress and was the top Democrat on the Sept. 11 commission.