'That certainly was the biggest obstacle," said Chris Nelson, a missile defense expert with the state Department of Military and Veterans Affairs.

President Bush's announcement came as a congressional conference committee was putting the finishing touches on a defense authorization bill that includes $786 million for construction of a missile test bed in the North Pacific.

Some of that money would be used to deploy test interceptors to new silos at Fort Greely in Delta, said Lt. Col Rick Lehner of the Ballistic Missile Defense Organization. The federal money would also include upgrades for the state-funded rocket launching site in Kodiak, which will be used for anti-missile tests under the administration's plan.

The Bush plan announced last summer would convert the Fort Greely test facility into a rudimentary missile defense system by 2004 if tests are successful. However, the 1972 ABM treaty allowed testing only, so the groundbreaking in Alaska could have been considered a treaty violation. Government officials in Russia had raised that point.

But the treaty allowed either country to withdraw with six months' notice. Thursday's announcement will allow construction in Alaska to begin next spring with no risk of a violation, state and federal officials said.