WASHINGTON -- The nation's leading presidential candidates took verbal shots at each other again today over the Iraq war.

Democrat Barack Obama pledged anew this morning that as president he would end the Iraq war, withdrawing American combat troops by two years from now, and focus the military's power on winning "a war that we have to win" in Afghanistan.

In a 35-minute speech at the Woodrow Wilson Center in Washington, Obama stressed foreign policy for a second straight day as he prepares for trips to Iraq and Afghanistan and to Europe and elsewhere in the Middle East. U.S. Sens. Jack Reed, D-R.I., and Chuck Hagel, R-Nebraska, are slated to accompany Obama to Iraq and Afghanistan

Obama framed his war plans as part of a broader geopolitical strategy that would, he said, strengthen U.S. alliances, break the nation's dependance on foreign oil and secure nuclear weapons around the world.

The speech had a political element, too: The Democratic senator from Illinois attacked Republican presidential candidate John McCain for perpetuating the policy of President Bush that, in Obama's words, "focuses on the tactics of fighting a war without end" in Iraq, while the situation in Afghanistan deteriorates.

Early this afternoon, McCain, meanwhile, spoke about Afghanistan.

In remarks prepared for delivery in Phoenix, the Arizona senator attacked Obama for opposing the U.S. troop surge that has improved security in Iraq.

"It is precisely the success of the surge in Iraq that shows us the way to succeed in Afghanistan," McCain said. "It is by applying the tried and true principles of counterinsurgency -- which Senator Obama opposed -- that we will win in Afghanistan."

-- John Mulligan of the Journal Washington Bureau