A number of US states are considering legislation to lower the legal drinking age from the current standard of 21 - if only to allow troops coming home from Iraq to drink.

The move would defy a generation of federal law and public opinion, which is strongly opposed to lowering the drinking age. In 1984 Congress set a uniform legal age of 21, threatening to cut highway funding to states which did not comply.

Despite the risk of penalties, however, seven US states are exploring lowering the drinking age - partly for under-age Iraq war vets and more broadly in recognition that teenagers are going to drink anyway.

"If you can take a shot on the battlefield you ought to be able to take a shot of beer legally," said Fletcher Smith, who has sponsored legislation to lower the drinking age in South Carolina.

Kentucky, Wisconsin, and South Carolina have introduced legislation to lower the drinking age for troops to 18.

Four other states - Missouri, South Dakota, Minnesota, and most recently Vermont - would extend the privilege to the general population. However, South Dakota would only allow 18-20 year olds to buy low-alcohol beer. Advocates of a lower drinking age argue that teenagers are drinking, and that the secrecy encourages binge drinking among young people.

"Our laws aren't working. They're not preventing underage drinking. What they're doing is putting it outside the public eye," Hinda Miller, a Vermont state senator, told reporters yesterday, after a committee took up her bill to study lowering the drinking age.

"So you have a lot of kids binge drinking. They get sick, they get scared and they get into trouble and they can't call because they know it's illegal."

While the move would be popular with college students and other young people obliged to pay for fake ID if they want a night on the town, there is concerted opposition to lowering America's drinking age.

Mothers Against Drunk Driving and other pressure groups say raising the drinking age a generation ago has cut traffic related deaths among young people by 13%.

States that do lower their drinking age would also pay a heavy penalty under current legislation that would require them to forfeit 10% of their highway fund from the federal government.