President Bush lamented the deaths of 14 Marines in Iraq Wednesday, calling the deadly attack a "grim reminder" America is still at war.

"These terrorists and insurgents will use brutal tactics because they're trying to shake the will of the United States of America. They want us to retreat," Bush told some 2,000 state lawmakers, business leaders and public policy experts gathered here.

The president spoke on a day when a Marine amphibious assault vehicle patrolling during combat operations in the Euphrates River valley hit a roadside bomb, killing 14 Marines from the same Ohio battalion that lost six men two days ago.

"Make no mistake about it," Bush said. "We are at war."

The latest deaths come as his administration is talking about handing more security responsibility over to the Iraqis and drawing down U.S. forces next year. At least 1,820 members of the U.S. military have died since the Iraq war began in March 2003, according to an Associated Press count.

Bush reiterated that he will not set a timetable for withdrawal. He said troops could return home once Iraqi forces have been adequately trained. "As Iraqis stand up, American and coalition forces will stand down," he said.

He said the families of fallen troops can know that the United States government will "honor their loved ones' sacrifice by completing the mission."

"The violence in recent days in Iraq is a grim reminder of the enemies we face," Bush said.

On the first full day of his more than monthlong stay at his ranch in Crawford, Bush flew aboard Marine One to Grapevine where he addressed The American Legislative Exchange Council. The council of state legislators was gathered to exchange ideas and work toward what is described as "a limited government that promotes free markets and individual liberties."

Bush boasted about gains in the U.S. economy and his recent legislative victories on issues, including trade and energy. He encouraged lawmakers, when they return from their August recess, to address the future of Social Security, a centerpiece of his domestic agenda that is languishing.

"My first question to members of Congress is `How can you go back to your districts, when you look at the facts, and stand up in front of young workers and look 'em in the eye and say the future's bright for you knowing full well somebody's going to be paying payroll taxes in the system that's going broke?"' Bush said.

He also urged the Senate to confirm John Roberts to the Supreme Court because "he will not legislate from the bench." The Senate needs to conduct its confirmation hearings in a way that brings "dignity" to the process, and seat Roberts on the nation's high court before it reconvenes in early October.