He said he welcomed traveling for the 2006 midterm elections in November. "I've got one more off-year campaign in me as a sitting president, and I'm looking forward to it," he said. "As you know, I like to get out and tell people what's on my mind."

The eavesdropping program dominated the domestic policy questions at the news conference, which Mr. Bush used as another volley in his weeklong campaign to push back against both Democrats and Republicans who question the program's legality. Senate Judiciary Committee hearings into the program are to begin next month.

"There's no doubt in my mind it is legal," Mr. Bush said.

He reiterated that the program, which intercepts international phone calls and e-mail messages of people in the United States suspected by the government of having links to Al Qaeda, was crucial to national security, and declared that he had the constitutional authority in wartime to order it. He said that after the Sept. 11 attacks he had asked people like Lt. Gen. Michael V. Hayden, then the director of the National Security Agency and now the principal deputy director of national intelligence, to come up with plans to protect against terrorist attacks.

"And so he came forward with this program," Mr. Bush said. "In other words, it wasn't designed in the White House; it was designed where you expect it to be designed, in the N.S.A."

Mr. Bush took issue with a questioner who asked why he felt the need to circumvent the 1978 Foreign Intelligence Surveillance Act, which requires court warrants for wiretaps.

"Wait a minute," Mr. Bush said. "That's a — there's something — it's like saying, you know, 'You're breaking the law.' I'm not." He said that the surveillance act "was written in 1978" and that now "it's a different world."