Arizona's long-running effort to keep housing and other developments from getting too close to its military bases may have gotten a boost Thursday from a legal opinion meant to clarify a state law passed four years ago.

But so far, the jury's still out.

The most significant effect of the opinion by Arizona Attorney General Terry Goddard, if it is followed by Maricopa County, would be to ban development on county land around an auxiliary training field used by Luke Air Force Base.

But Maricopa County Supervisor Max Wilson, District 4, released a statement saying he's not certain the opinion offers sufficient guidance.

"I have concern for both Luke and for the private-property owners surrounding the base," Wilson said. "At this time, it is unclear whether the attorney general's opinion really clarifies the issue for anyone concerned."

Some landowners around the field said the opinion wasn't helpful to them. Michael Francis, a spokesman for the West Valley Community Action Coalition, which represents landowners near Luke and the field, said the opinion doesn't say whether the county should compensate property owners if it stops issuing building permits.

"It's a very narrow opinion that has been broadly viewed," Francis said.

Since the state law was passed, building permits have been issued for about 25 single-family houses in the buffer zone, according to information available Thursday from the county.

Goddard's opinion, if the county falls in line with it, would buffer the field known as Aux 1, which is 15 miles northwest of Luke. Aux 1 is in Surprise, but the buffer zone around the base also contains county land and state land.

Peoria and several other West Valley cities lobbied for state laws protecting Luke because of the positive economic impact the base has on surrounding communities.

They contended the base needs open land around it so homes and businesses won't be subjected to noise from planes and the risk of crashes.

John Schell, Peoria's intergovernmental director, said Aux 1 is used each year for 12,000 to 13,000 "must-do" training exercises that can't be carried out at the main base.

The release of Goddard's opinion bodes well for that aspect of Luke's operation, he said.

"This is a huge deal and very, very important for Luke to continue its mission," said Schell.

A statement issued by Luke Air Force Base said the base is "vitally interested" in land-use decisions that protect people living near the base, its auxiliary airfields and the flight paths of its planes. Compliance with state law will ensure the safe operation of Luke's flight training missions, the statement said.