Ah ha! I see my reputation precedes my post here.
Yes, I'm against it and would definitely vote against lowering the voting age on a binding referendum, but that wasn't the question. The question only regarded the legality of jurisdictions allowing 16-year-old residents to vote. I don't think there's an argument to be made based on age, since the constitution expressly prohibits setting local minimum voting age higher than 18. 16 is not greater than 18 so you're safe. If there's a legal argument to be made against it, it would have to rest upon the part of citizenship. (Citizens, not just residents, can vote. You can be over 18 but if you're not a citizen you cannot legally vote.) The question is, then, at what age does a person enjoy the rights generally appertaining to those of the citizen? There is some argument that this age is viewed as 18 by the legal community. For example, foreign-born children before the age of 18 may automatically become US citizens when a parent becomes a US citizen, but if the parent becomes a US citizen after the child's 18th birthday, then the child is not automatically a US citizen when the parent becomes naturalized. Then the thinking that applies to foreigners who become naturalized citizens would logically apply to natives who become citizens by virtue of age. That is, when a person reaches the age of 18 he begins to enjoy certain rights and certain burdens. Among those, I think, is the right to vote, and the burden of loyalty.
There are some inconsistencies. One must be 21 to purchase a handgun and to purchase alcoholic beverages as well, yet one can purchase cigarettes at 18 and join the military at 18. Then again, those limitations are probably not related to the lofty ideal of citizenship, but rather related to logistics, medical concerns, or safety. Sort of like getting a driver's license at 16, getting certified as an open water SCUBA diver, or watching certain movies in theaters at 13. Those limitations clearly have nothing to do with citizenship. They have to do with personal safety, public safety, and psychiatric or medical considerations. Perhaps the handgun, cigarette, and alcohol policies are based on such factors as well, and it just happens to be the case, but unrelated, that the cigarette-purchasing age limit is the same as the voting age limit.
