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Republican presidential candidate Sen. John McCain addresses the NAACP on Wednesday. He received a polite reception during a speech that emphasized funding of education.

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.

The woman, wearing a union T-shirt, said she was making $17,000 a year and cannot afford housing, gas, food or health care for her children. "We cannot continue this way," she said.

McCain said the point of his education platform was to boost pay for "a great and outstanding teacher like you" and other educators who are passionate about their work.

"I want to reward good teachers," said McCain.

Members of the audience said afterward they were glad to have heard from McCain, even if it didn't change their minds.

"Winning votes, I'm not so sure, but friends, yes," the Rev. Ronald Terry, pastor of New Friendship Baptist Church in Macon, Ga., said of McCain's appearance.

Marjory Shields, a Penn State extension nutritionist from Croydon, Pa., said McCain said nothing to make her waver from her support of Obama.

"I gave him the courtesy of listening to his platform. I thought that in order for me to make an informed vote this November I really need to hear what all the candidates have to say," Shields said.

"As far as my opinion on his speech, I feel he did not address certain key issues I wish he would have elaborated on," such as more specifics on education funding, she said.

McCain said vouchers and merit pay for teachers whose students perform well are two important ways to help kids in failing schools.

"After decades of hearing the same big promises from the public education establishment, and seeing the same poor results, it is surely time to shake off old ways and to demand new reforms," he said. "That isn't just my opinion. It is the conviction of parents in poor neighborhoods across this nation who want better lives for their children."

Both the merit pay and voucher proposals have met stiff opposition from teachers unions. Obama has indicated he would support some kind of merit pay system for teachers, if teachers help craft it.

Later Wednesday, McCain traveled to Omaha, Neb., where he toured Werner Enterprises, a trucking company, and again promoted his plan for a summer suspension of the federal gas tax to help drivers cope with surging fuel prices.

Werner executives said that a yearlong gas tax holiday would save them approximately $40 million, which could be spent on making their trucks more efficient.

Asked what individual Americans could do to lower the price of gas, McCain said they "can practice conservation" and pressure Congress to allow more offshore drilling for oil.

Meanwhile, Obama warned Wednesday about the danger of "fighting the last war" as he pledged to focus on emerging nuclear, biological and cyber threats if elected president.

Among those joining him for a panel discuss at Purdue University in West Lafayette, Ind., were two potential running mates, Sen. Evan Bayh, D-Ind., and former Sen. Sam Nunn, D-Ga. As the former governor of a Republican state, Bayh could help Obama. Nunn, a defense expert from the South, would burnish the ticket's experience.

When asked if he were interested in the job or had provided material to vetters, Bayh repeatedly referred reporters to the Obama campaign. Nunn said he thought an Obama-Nunn ticket was unlikely.

"If anyone offered me any high office in U.S. government, I'd be greatly honored and I'd talk to him. Certainly I would talk to Sen. Obama if he wanted to talk about it, but I think the chance of an offer are pretty slim," Nunn said.

Obama said two goals of his administration would be to secure all loose nuclear material during his first term, as well as rid the world of nuclear weapons.