The Virginia Democrat, speaking on NBC's "Meet the Press," said the Bush administration has failed diplomatically and Congress needs to correct that situation.
"I think this has been a botched occupation. It's been going on for four years, after the purely military part of it was done," Webb said.
"So we reached a point ... where we have to come together as a Congress and attempt to bring some order into this."
Meanwhile, Sen. Lindsey Graham, R-S.C., defended the U.S. military surge and countered that the war is "very much part of a global struggle" against al-Qaida and radical Islamic terrorism.
"The new strategy of getting more combat power where al-Qaida and others reside I think has been enormously successful," Graham said. "Al-Qaida has come to Iraq. (Osama) bin Laden has said this is the equivalent of the third world war. So what's going on in Iraq is not about us wanting to own Iraq; it's about us supporting a form of moderation not known to the Mideast."