Republican Senator Lindsay Graham of South Carolina, responded to Obama's remarks on behalf of McCain.
"If we had followed his (Obama's) advice, Iraq would have crumbled, al-Qaida would have won and Iran would gain influence," Graham said during a conference call.
It was the second straight day of debate over Iraq policy between the campaigns.
On July 3, Obama kicked off speculation over where his Iraq policy would go after he said he might "refine" his Iraq policy following an upcoming planned trip there.
He quickly sought to put down that speculation.
In Monday's op-ed piece, Obama said he would send at least two more combat brigades to Afghanistan while leaving "a residual force in Iraq."
McCain's campaign said the Arizona senator would speak for his plan for Afghanistan on Thursday.
His advisers declined to say whether he agreed with Obama's Afghanistan proposal before the speech.
(Xinhua News Agency July 15, 2008)