IS THERE SOME iron law that guarantees that government bureaucracies must always mushroom in size? Apparently not, if the most recent Census Bureau figures on government employment are a guide. The bureau reports that state and local governments employed some 13.1 million people last year; reducing that number to take account of part-time workers, you have "full-time equivalent" employment of 10.9 million people. That is a decline from the corresponding figure of 11.0 million for 1980, and a sharp departure from the trend that had seen state and local government full-time equivalent employment grow by an average of 200,000 a year since 1974 and by larger numbers between 1960 and 1974. In 20 years, employment by state and local governments basically doubled; now the trend is the other way.

In this respect, government at lower levels is reflecting what has been happening at the federal level for some time. Despite overblown rhetoric about pointy-headed federal bureaucrats, the number of civilian federal employees has not been increasing rapidly in recent years. In fact, it has remained level, at about 2.9 million people, since 1967. Note that that figure is much lower than the number of people employed by the states and localities, a number that includes 5.3 million, mostly teachers, in education. True, the number of civilian Defense Department workers has declined by 200,000 since 1970, and the number of Post Office employees has gone down in the same period by some 65,000, which means that the number of federal employees in all other departments has risen by some 260,000 in that period. But even this last number seems to have stabilized, if we can judge by the figures for 1980 and 1981.

It is true that the number of employees can understate the level of government spending and involvement in people's lives: government can and does subcontract much of its work out to private firms, and some jobs in government, as in industry, are being automated out of existence. Nonetheless, the tendency for government employment to stabilize and even fall teaches an important lesson: bureaucracy is not entirely out of control. We got more government jobs because officials responsible and exceedingly sensitive to the voters wanted certain work done -- whether it was waging a war in Vietnam or expanding the range and generosity of many local government services. Now that voters no longer want increased services, the number of employees falls.

In this connection, it is important to note that the number of both federal and of state and local employees fell in 1981 -- before most of the Reagan administration's budget cuts had a chance to take effect. Thus even in the Carter years, a Democratic Congress, a Democratic administration in Washington and Democratic governments in most states and big cities were already responding to the public demand that found expression electorally in the Reagan landslide and Republican congressional victories of 1980. Voters like to complain that officeholders don't listen to them, but the evidence suggests, on the contrary, that there is a hair-trigger responsiveness among American politicians that is translated, sometimes crudely but effectively and quickly, into public policy.