If the voting age were lowered, would that necessitate changing other laws to bring them into alignment? Of course not. We use a wide variety of chronological ages to draw lines between minors and adults when it comes to smoking, driving, viewing violent or sexually explicit movies, being eligible for the death penalty and drinking alcohol. Although the specific ages used for these purposes often lack a good rationale, there is no reason lowering the voting age would require lowering, say, the drinking age, any more than allowing people to drive at 16 should permit them to drink or smoke at that age as well.
In addition to the scientific case for lowering the voting age, there is also a civic argument. Consider the dozen or so countries like Argentina, Austria, Brazil and Nicaragua that allow people to vote at 16 in national, state or local elections. In such countries, voter turnout among 16- and 17-year-olds is significantly higher than it is among older young adults.
This is true in parts of the United States as well. In Takoma Park, Md., a city that permits 16- and 17-year-olds to vote in local elections, that age group is twice as likely to vote than are 18-year-olds.