Take a break as you fill out your 1040 form, and play this game: suppose you could choose which government entities your tax dollars support -- and in what proportion. Since it's a thought experiment, let's assume that local and state government functions are part of the list. What percentages will you assign to which departments, agencies and programs?

Some people will split their taxes between the local police and national defense and leave it at that. Some will assign it all to the Environmental Protection Agency. Taxpayers from red states will choose differently from taxpayers from blue states. But polling data tells us enough about the government services people value to permit reasonably confident predictions about the national results.

Police, fire, water and sewage, courts and prisons and national defense will get far more money than they would ever have the nerve to request. The allocations for national parks, environmental protection, air-traffic control and highways will probably be many times their current budgets. But my first point (match my prediction against your own choices) is that almost all the choices will be for tangible services. Most of them will be for services that fall under the classic understanding of a ''public good'' -- something that individuals cannot easily provide on their own and that is shared by all (police protection, clean air).

My second point is that allowing taxpayers to name where their tax dollars go would put large segments of local, state and federal government out of business. To see what I mean, go to the Web and bring up the organizational chart of any government department. Some of the boxes will catch your eye as something you might like to support (mine safety, the national archives) but there will be plenty of other boxes about working groups, directorates for planning or administration or diversity, offices of compliance exemption or regulatory development, all of which sound like a ton of bureaucracy for an ounce of output. Might you use your tax dollars to support a mine inspector or an archive curator? Quite possibly. Will you line up to support any of the boxes that sound like gobbledygook? Unlikely. Much of the apparatus of government does nothing that ordinary people, making sensible judgments, would willingly pay government to do.