Laws that require a tape measure to enforce are usually more trouble than they’re worth.Well that was quick. Wednesday it was illegal to smoke in parks. By Thursday night, it was only kind of illegal.Last night, Parks and Rec Superintendent Tim Gallagher relaxed the total ban that would have gone into effect on April 1, insisting that it was too broad and unenforceable. In its place, Gallagher substituted something even less enforceable: a distance-based ban that will make it illegal to smoke or chew tobacco within 25 feet of other people and beaches.It’s great that Gallagher so swiftly recognized the ridiculousness of the outright ban. But why backtrack only halfway?As the P-I notes, we already have one 25-foot-smoking law — you’re not allowed to light up near the door of a bar — that isn’t enforced. Who needs more vague, burdensome arcana like that?