Democratic challenger John Kerry has criticized President Bush's first response to the terrorist attacks of September 11, 2001. President Bush says he has acted decisively since that violence to make the nation safer.
President Bush was reading with school children in the state of Florida, when the first hijacked passenger jet slammed into the World Trade Center three years ago.
White House Chief of Staff Andy Card informed the president, and Mr. Bush stayed in the classroom for another seven minutes before excusing himself.
That episode has gained greater prominence in this campaign, following a highly critical movie about the president, which shows him sitting in the classroom with a clock ticking off the minutes until he moves.
Senator Kerry told a conference of ethnic minority journalists in Washington that he would have acted sooner.
"First of all, had I been reading to children and had my top aide whisper in my ear, 'America is under attack,' I would have told those kids very politely and nicely that the president of the United States had something that he needed to attend to," Senator Kerry said.
Campaigning in the Midwest state of Ohio, President Bush says his actions since that violence have made America and the world safer by toppling governments in Afghanistan and Iraq, and pursuing what he calls ideological extremists.
"They are trying to shake our will and our confidence. One of the lessons of September the 11 is we face a deadly foe, who will kill on a moment's notice to try to shake our confidence and our will," the president said.
Senator Kerry says Mr. Bush lacks the credibility to lead the U.S. military, because he did not sufficiently exhaust peaceful means of disarming Saddam Hussein, before he sent U.S. troops into Iraq.
"You got to be able to look parents in the eyes, if they lose their son or daughter, and say to them, 'I tried to do everything in my power to avoid this, but we had no choice as a nation, as a people, because of the challenge to our country, to our fundamental values from a threat that was real and imminent.' I believe in my heart of hearts and in my gut that this president fails that test in Iraq," he said.
The president's primary justification for invading Iraq was the immediacy of the threat from weapons of mass destruction. As none of those weapons has yet been found, Senator Kerry says, Mr. Bush misled the nation into a war where he did not understand the nature of the threat.
President Bush says Senator Kerry is flip-flopping on Iraq, after originally supporting action to disarm Saddam Hussein.
"Now, the United States Congress looked at the same intelligence I looked at, the exact same intelligence, and came to the same conclusion," Mr. Bush noted. "Members of both political parties looked at the intelligence. My opponent looked at the very same intelligence, and came to the same conclusion."
With less than 90 days before the election, most public opinion polls show Americans evenly divided between President Bush and Senator Kerry. That focuses even more attention on the more than a dozen so-called swing states that could go to either candidate.
After his appearance in Ohio, President Bush is campaigning in the swing state of Michigan. Senator Kerry and running mate John Edwards are looking for votes in the state of Missouri.