A dispute over whether teen-agers should be used to enforce underage smoking laws leads to the defeat of a juvenile smoking bill. Supporters say the state needs to enact tougher laws to keep cigarettes out of the hands of those under 18. But a bill that would make it illegal for juveniles even to attempt to buy tobacco and make possession illegal dies in the last day of the session as Representatives such as Ken Legan of Halfway find fault with Representative Tom Hoppe of Kansas City acceptance of a Senate change letting teens as young as 15 participate in retail tobacco stings. Legan finds it unacceptable as do others in the House. It didn’t pass this year. Those who backed it say Missouri’s share of nearly 10-Million dollars in federal funds has been placed in jeporady.