TAMPA, Fla. - Addressing a Republican convention that has largely ignored the last Republican to serve in the White House, former Florida Gov. Jeb Bush on Thursday emphatically defended his brother, former President George W. Bush, and demanded that President Obama stop blaming his predecessor for all his problems.

"My brother ... is a man of integrity, courage and honor and, during incredibly challenging times, he kept us safe," Jeb Bush said in an off-script moment that brought convention delegates to their feet.

Until that moment late in the last day of a three-day convention, George W. Bush was a muted presence at the convention just four years after he left office.

Conservatives blame George W. Bush for expanding the scope of government, particularly Medicare, and are mindful of the former president's record-low popularity ratings. And except for a video of the former president, which also featured his father, former President George H.W. Bush, the convention has largely ignored its last president.

That made Jeb Bush's full-throated defense of his younger brother all the more distinct.

But it was Obama's constant blaming of George W. Bush for so many of the nation's current problems that prompted Jeb Bush's most stinging missive.

"Mr. President, it is time to stop blaming your predecessor for your failed economic policies," he said. "You were dealt a tough hand, but your policies have not worked."

Bush hinted earlier in the day that he would divert from his prepared remarks to raise the profile of his brother. Nevertheless, it was a rare unscripted moment on the final day of a tightly controlled convention.

When he finished, Bush said, "Now that I've gotten that off my chest, let's talk about our kids and education."

Painting Republicans as the party that cares about the future of the nation's children, Bush laid into teachers unions as opponents of change, called for more school choice and greater flexibility for states to tackle education reform on their own.

"There are many people who say they support strong schools but draw the line at school choice," Bush said. "I have a simple message for these masters of delay and deferral: Choose. You can either help the politically powerful unions. Or you can help the kids."

Obama's campaign sought to cast doubt on Bush's support for Romney. Obama spokesman Danny Kanner noted Bush "has said that Mitt Romney's Republican Party is too extreme for Ronald Reagan or George H.W. Bush. And just this week, Bush said the party should 'just stop acting stupid' on immigration and embrace a broader, inclusive message."