"This nation may never be perfect," Obama said Tuesday in Philadelphia, "but it can always be perfected."

The Democratic presidential hopeful said he rejected racially charged comments made by the Rev. Jeremiah Wright but couldn't reject the man.

"The remarks ... expressed a profoundly distorted view of this country," Obama said, adding, "I could no more disown him than I could disown the black community ... or my white grandmother."

Wright's characterization that the United States is racist reflects the times in which he grew up, when racial divisions were deep and discrimination rampant, Obama said.

"This is the reality in which Reverend Wright and others grew up," he said.

But people of all races must move forward, Obama said, which requires "all Americans to realize that your dreams do not have to come at the expense of my dreams."

"Working together, we can move beyond some of our old racial wounds," Obama said. "We have no choice ... if we are to move on the path to a more perfect union."