Legal age requirements should never stand alone. They should be flexible and pragmatic and paired with educational and cognitive requirements for the exercise of legal maturity...
16-year-olds who want to start voting should be able to obtain an “early voting permit” from their high schools upon passing a simple civics course similar to the citizenship test. Besides increasing voter registration, this system would reinforce the notion of voting as a privilege and duty as well as a right — without imposing any across-the-board literacy tests for those over 18.
I would go further: Imagine a 'democracy' class in which students researched and debated issues of public concern -- immigration, war and foreign policy, civil liberties, health care, crime and justice, etc. -- learning about social science and political philosophy, and applying their knowledge to the real-world problem of who to vote for. What better way to prepare the next generation of citizens? Of course, it would depend upon good teachers offering critical but unbiased guidance. And anti-rationalist parents will be outraged at what they can only imagine to be 'indoctrination'. Cf. my old post: Teaching Values.
As Peter Levine writes in his excellent paper, 'Youth-Led Research, the Internet, and Civic Engagement' [PDF], pp.11-12:
public schools court controversy whenever their students engage in political advocacy and/or “faith-based” community action. Yet forbidding politics and religion drastically narrows the range of discussion and action; as a result, service-learning often becomes trivial.(He goes on to recommend "public-interest research using the new digital media" as a more 'neutral' alternative for public schools.)
Many of the best programs are found in Catholic high schools, where service experiences are connected to a challenging normative and spiritual worldview: post-Vatican II Catholic social thought. There is no evidence that these programs cause their graduates to agree with the main doctrines of Catholic theology; but students do develop lasting engagement with their community.
On his blog, Levine adds:
Developmental psychology tells us that civic experiences in adolescence have profound, lifelong effects on civic participation, whereas experiences in adulthood tend not to affect people much. Therefore, if you want to build a public, you must give teenagers positive civic opportunities.
The opportunity to vote in national elections would be a good start. But it is possible to make do in the meantime, as Kids Voting USA demonstrate:
After classroom preparation, students take part in a voting experience using a ballot that mirrors that of the adults with the same candidates and issues. This “real life” practice dispels the mysteries of the voting process and reinforces the knowledge and skills gained through Kids Voting classroom activities...
It is the combination of classroom instruction, family dialogue and an authentic voting experience that makes Kids Voting USA a powerful strategy for achieving long-term change in voting behavior.
I recall reading elsewhere that these programs even result in immediate increases in voter turnout, due to broader family involvement.