U.S. Sen. Chuck Hagel said gains made in Iraq are easily reversible if that nation's government can't take advantage and make political progress.
The Nebraska Republican, a harsh critic of President Bush's Iraq policy, accompanied Democratic presidential candidate Barack Obama on the trip.
Hagel said Thursday he saw tactical gains in Iraq but that they came at a high price.
Hagel said President Bush's decision last year to dispatch 30,000 more troops to Iraq has cost more than 1,000 American lives and billions of dollars.
Asked how Republican Senate colleagues reacted to his traveling with the presumed Democratic nominee, Hagel said he hadn't really discussed it with them and, "I didn't ask their permission."