CINCINNATI — John McCain told the NAACP and some skeptical black voters Wednesday that he will expand education opportunities, partly through vouchers for low-income children to attend private school.

The likely Republican presidential nominee addressed the annual convention of the National Association for the Advancement of Colored People, the nation's oldest civil rights organization.

In greeting the group, McCain praised Democrat Barack Obama's historic campaign but said the Illinois senator is wrong to oppose school vouchers for students in failing public schools. It is time, McCain said, to use vouchers and other tools like merit pay for teachers to break from conventional thinking on educational policy.

Obama, he said, has dismissed support for private school vouchers for low-income Americans.

"All of that went over well with the teachers union, but where does it leave families and their children who are stuck in failing schools?" the Arizona senator asked. "No entrenched bureaucracy or union should deny parents that choice and children that opportunity."

In fact, Obama has spoken in favor of performance-based merit pay for individual public school teachers, even telling the National Education Association, the country's largest teachers union, the idea should be considered in a speech last year.

McCain received mostly polite applause in a room with some empty seats, two days after Obama received an enthusiastic reception from a standing-room only audience hoping to see him become the first black president.

In his speech, McCain lauded Martin Luther King Jr., as a leader who "loved and honored his country even when the feeling was unreturned, and counseled others to do the same."

In praising King to the NAACP, McCain used similar language to his mea culpa in April on the 40th anniversary of the civil rights leader's assassination, saying he had been wrong to vote against a federal holiday honoring King.

The NAACP gathering heard on Monday from Obama, who said he would push the government to provide more education and economic assistance, but he also drew big cheers when he urged blacks to demand more of themselves.

"Whatever the outcome in November," McCain told the crowd Wednesday, "Senator Obama has achieved a great thing, for himself and for his country, and I thank him for it. ... Don't tell him I said this, but he is an impressive fellow in many ways."

During a question-and-answer session, McCain also sought to assuage a frustrated Head Start teacher who complained that her salary from the federal program simply isn't enough.