NEW YORK—George W. Bush accepted the Republican nomination for president last night, casting his first term in the shadow of the Sept. 11 attacks and defending his administration’s tactics and policies in the war on terrorism.

“In the heart of this great city, we saw tragedy arrive on a quiet morning,” Bush told thousands of flag-waving delegates at Madison Square Garden. “Since that day, I wake up every morning thinking about how to better protect our country. I will never relent in defending America, whatever it takes.”

Speaking just miles from Ground Zero, Bush repeatedly invoked the attacks of Sept. 11 and said he had spent the past three years making the world safer by defeating the Taliban in Afghanistan and toppling the government of Saddam Hussein in Iraq.

“Free societies in the Middle East will be hopeful societies, which no longer feed resentments and breed violence for export,” Bush said.

Laying forth his vision for a second term in office, the president said he would promote an “ownership society” by reforming social security, expanding access to health care and making his tax cuts permanent.

The president vowed to widen access to higher education, calling for greater funding of the federal government’s beleaguered student aid program. “By raising performance in our high schools and expanding Pell grants for low- and middle-income families, we will help more Americans start their career with a college diploma,” Bush said.

Roughly 9 percent of Harvard undergraduates qualify for Pell grants, according to the Office of Financial Aid.

Bush also touted his administration’s signature education package, the No Child Left Behind Act, and said nationwide student testing would hold schools accountable for their performance.

“We are insisting on accountability, empowering parents and teachers, and making sure that local people are in charge of their schools,” Bush said, drawing some of the largest applause of the night.

And in a brief but resolute section on values, the president took a pointed jab at the Supreme Judicial Court of Massachusetts for its ruling last year that legalized gay marriage in the state. “Because the union of a man and woman deserves an honored place in our society, I support the protection of marriage against activist judges,” Bush said.

But Bush did not give mention to a proposed constitutional amendment banning gay marriage, which he supports.

The president reflected upon the accomplishments of his first term in office, contrasting his record against that of his opponent, Sen. John F. Kerry, D-Mass., whom Republicans have painted as inconsistent in his views.

Speaking directly to the delegates assembled on the floor below him, Bush said, “Even when we don’t agree, at least you know what I believe in and where I stand.”

Bush ripped into Kerry for what he said were the senator’s “tax-and-spend” policies.

“He’s proposed more than two trillion dollars in new federal spending so far,” Bush said, “and that’s a lot, even for a senator from Massachusetts.”