Eighteen year olds can join our armed forces and fight to defend our freedom, but not legally buy beer.  This inconsistency I think constitutes a disgrace, and highlights some weaknesses of our democratic process.

Eighteen year olds have been eligible to serve in the U.S. military since our nation’s founding.  Many states lowered the drinking age to 18 in the 1970s, but raised it back to 21 in the 1980s.  I lost the legal right to drink twice during college.

I believe in individual freedom, but freedom requires the capacity to understand the consequences of and take responsibility for our actions.  Both restricting freedom until people reach maturity as well as making the most consequential life choices the last freedoms young people attain make sense.

But joining the armed forces is arguably the most consequential of life’s choices.  Military service can of course be fatal in wartime – more than 400 teenagers died in combat in Iraq and Afghanistan.  Survivors of combat bear serious emotional scars.  Telling 18 year olds that they are mature enough to serve but not to be served is insulting.

Such legal inconsistencies, however, rarely emerge explicitly.  The Federal government is not a single person, but rather the executive and legislative branches plus thousands of bureaucrats.  Different Congresses decided that 18 year olds could serve but not be served.  Consequently laws which stay on the books forever comprise a weakness of our system.  Some states have sunset provisions for legislation, which require periodic reauthorization of agencies and their demise if public support evaporates.  Federal laws remain in effect until Congress repeals them.

The mechanism of raising the drinking age illustrates the bankruptcy of our federalism.  The National Minimum Drinking Age Act of 1984 withheld 10% of federal highway funds from states which did not comply.  America’s founders created a federal republic where states would check the national government’s power.  State governments addicted to grants from Washington cannot exercise the political deliberation which federalism requires.

More problematically, Congress raised the drinking age, essentially imposing prohibition, largely to address drinking and driving by teenagers.  Prohibition is troublesome both ethically (using the irresponsibility of some to justify denying freedom to others) and practically.  Binge drinking is a significant problem on college campuses, yet is a predictable consequence of prohibition.  When college students must break the law to drink they will consume more when they drink.

A higher drinking age might have appeared necessary to combat drinking and driving, but the necessity was really a product of government’s feeble efforts.  Suspending or revoking drivers’ licenses is used to punish offenders, but the intoxicated can still operate cars without a valid driver’s license.  Too often the drunk drivers who kill others have already have a suspended license; nationally 20% of fatal accidents involve drivers without a valid license.

Sobriety check points are also used to combat drunk driving, but sometimes fail to ticket a single drunk driver.  The Chicago Tribune found that only 7% of citations issued at check points in Illinois were for drunk driving.  Check points produce tickets for driving without insurance and expired licenses or car tags, but get few impaired drivers off the road.

Electoral politics’ emphasis on appearances and intentions over results helps explain the persistence of ineffective policies.  Our representatives win reelection by appearing to act in our interest.  Government does not have a bottom line like profit and loss, so voters have difficulty punishing representatives when their actions prove costly and ineffective.

If 18-20 year olds cannot be trusted with a beer, they shouldn’t be trusted with an M-16.  Hopefully this contradiction might soon be resolved.  Technology is one source of hope.  Ignition interlock systems, or “car breathalyzers” which require a driver to pass a breathalyzer test to operate his car, are more effective in preventing driving after drinking.  And three states have recently considered lowering their drinking age, reckoning that additional alcohol taxes may offset the loss of Federal highway dollars.  Perhaps the enduring lesson is not to trust a political process that produces such glaringly incongruous policies.

Daniel Sutter is the Charles G. Koch Professor of Economics with the Manuel H. Johnson Center for Political Economy at Troy University and host of Econversations on TrojanVision.  Respond to him at dsutter@troy.edu and like the Johnson Center on Facebook.