President ObamaReporting from Phoenix - Speaking to more than 5,500 veterans, President Obama on Monday renewed his commitment to dismantling Al Qaeda in Afghanistan -- a struggle he said was "fundamental to the defense of our people" -- and offered assurances that his healthcare overhaul would not touch veterans' medical benefits.

"This is not a war of choice. This is a war of necessity," Obama told the annual Veterans of Foreign Wars conference -- cautioning that the insurgency would not be defeated overnight. "Those who attacked America on 9/11 are plotting to do so again. If left unchecked, the Taliban insurgency will mean an even larger safe haven from which Al Qaeda would plot to kill more Americans."

With U.S. forces scheduled to leave Iraq by 2011, Obama pledged that in the future, he would only send service members "into harm's way when it is absolutely necessary."