It has been conceded for years that "You can't fight city hall." But it is possible to argue with city hall, and The Washington Post has recently been doing that by urging Mayor Barry not to try to go into the bond market to borrow $200 million.

Post editorials have pointed out that $200 million worth of 30-year bonds would cost about $400 million in interest. To redeem the bonds, the District of Columbia's taxpayers would therefore have to pay out $600 million. It might be cheaper to borrow from the Mafia's loan sharks.

The mayor and his spokesmen disagree with this advice and cite many reasons for going forward with the bond issue. In a recent letter published in The Post, Philip M. Dearborn, financial counselor to the mayor, added htis frank insight: "City officials have consistently reiterated the District's desire to be free to solve its own problems and manage its own affairs."

Dear, dear! Home Rule isn't even a teen-ager yet, and already it is impatient to be out on its own so that it can flex its muscles and prove its manhood.

Unfortunately, the District is not yet as adept at problem solving as it thinks it is. Those of us who have raised teen-agers know it is important to be patient and try to explain things in simple language. Like this:

The most prudent course is to avoid debt whenever possible.

Debt is easier to get into than it is to get out of.

When you're out, stay out.

If you are in and want to get out, you must have an income that is greater than your outgo. This can be achieved by increasing income, by reducing spending, or by a combination of the two. Any other course is an exercise in self-delusion.

Adding high interest payments to a debt for 30 years solves nothing. If funds are urgently needed now, short-term borrowing can be helpful, but only if there is immediate revision of spending and income plans that permit a surplus to become available -- not only for meeting interest payments but for whittling down the principal. As The Post has pointed out: "By saving money from the city budget -- the same amount that would go to interest payments on bonds -- and investing that money, the city could pay off its debt in less than 10 years." The saving to taxpayers would be enormous.

It might be useful if all of us were to spend one quiet evening at home with a standard history of the United States.

An hour or two of browsing would remind us that the American Revolution cost our side an estimated $140 million and left a debt in its wake of about $75 million, which our ancestors considered "simply appalling." The debt was an especially heavy burden because by 1786 we couldn't even raise enough revenue to pay the interest on the money we already owed.

We tightened our belts, began whittling away at the debt, and soon made "the full faith and credit" of the United States a meaningful term.

By 1835, we had paid off the debt, and in 1836 we passed the Deposit Act that set up rules for distributing the federal Treasury's annual surplus among the states.

However hard times soon overtook us. The surpluses disappeared and we began to borrow -- "temporarily." By 1941, the national debt had grown to $40 billion. Today interest alone costs the American taxpayer $100 billion a year.

We have no hope of paying off our public debt because we have permitted it to become so large that we cnanot raise taxes high enough to meet the interest costs, let alone have something left toward reducing the debt. For too many years we took the easy road and borrowed. Now we must live with the consequences.

This is the circle of frustration that President Reagan is trying to break. Many taxpayers and economists think Reagan's spending cuts make sense but his tax cuts do not. They are supporting the president out of desperation. Nothing else has worked, so must hope Reagan's plan will.

If Mayor Barry insists on selling the District into long-term bondage, we'll just have to pay the piper. But any family that has tried to borrow its way out of debt without first adopting a new budget in which income exceeded outgo can tell him, "It doesn't work that way, Mr. Mayor. Borrowing without retrenching just puts you deeper into the hole."