SAN FRANCISCO — Attorney General Mukasey, in an emotional plea for broad surveillance authority in the war on terror, is warning that the price for failing to empower the government would be paid in American lives. Officials “shouldn’t need a warrant when somebody picks up the phone in Iraq and calls somebody in the United States because that’s the call that we may really want to know about. And before 9/11, that’s the call that we didn’t know about,” Mr. Mukasey said yesterday as he took questions from the audience following a speech to a public affairs forum, the Commonwealth Club. “We knew that there has been a call from someplace that was known to be a safe house in Afghanistan and we knew that it came to the United States. We didn’t know precisely where it went.”

At that point in his answer, Mr. Mukasey grimaced, swallowed hard, and seemed to tear up as he reflected on the weaknesses in America’s anti-terrorism strategy prior to the 2001 attacks. “We got three thousand. … We’ve got three thousand people who went to work that day and didn’t come home to show for that,” he said, struggling to maintain his composure.

At the time of the attacks, Mr. Mukasey was the chief judge at the federal courthouse a few blocks away from the World Trade Center. He was selected as attorney general in part because of his experience overseeing terrorism cases, but he said that did little to prepare him to deal with the daily briefing he receives about the threat to America.

“It is way beyond — way beyond anything that I knew or believed. So, if I was picked for the level of my knowledge of what I actually see, that was a massive piece of false advertising,” he said. “There’s a lot going on out there.”

Asked about so-called profiling of Muslims, Mr. Mukasey said that tactic is not used at airports. However, he used blunt language to defend extra scrutiny the Justice Department gives to militant Islamic groups.

“So far as focusing investigations, we investigate where the threat is coming from. The threat is coming from Islamist extremism. It’s not coming from Calvinism,” the attorney general said. “We’d be out of our minds not to mention the waste of resources to look everyplace simply in the name of being correct.”

Mr. Mukasey quickly added that religion is never the sole basis for an investigation. “We don’t look at Muslims simply because they’re Muslims. That doesn’t happen,” he said.