Congress is about to vote on the Gramm/Rudman mandatory balanced budget plan. This plan would require the budget deficit to be reduced to increasingly lower levels over a five-year period until the budget is in balance. If Congress does not act to achieve those reductions, then the president would have authority to "sequester" or eliminate unilaterally automatic increases in entitlements, except Social Security, and to make across-the-board cuts in defense and nondefense programs in order to reach the deficit-reduction target. Before Congress is stampeded, let us stop and think what's wrong with this proposal.

First, Gramm/Rudman is an unprecedented and probably unconstitutional shift of power from the legislative to the executive branch. But as one supporter sheepishly explained, "It's only for five years." With this additional power, Ronald Reagan, if he plays hard ball (and who thinks he will not?), could effectively dismantle the nondefense portion of the budget and wreak havoc with America's poor.

Under Gramm/Rudman in October of next year, when Congress would have to comply with this measure, we would have to come up with anywhere from $20 billion to $50 billion in additional annual deficit reductions, according to the Congressional Budget Office. Since the president has consistently ruled out any tax increase or defense cuts and wants Social Security to be a separate fund, he is likely to veto any congressional action to meet the target by raising taxes or cutting defense. Unless Congress musters a two-thirds majority on a veto override to raise taxes, the president would be required to cut across the board in the controllable portion of the defense and nondefense budget. That would mean a minimum of a 5 percent real cut in defense.

With each additional year as the deficit gap became larger and Congress could not get a two- thirds vote for tax increases, a bigger cut would be required for defense under Gramm/Rudman. This threatens to gut our readiness, to foreclose the option of building up our conventional strength, and to force us to rely more heavily than ever on offensive nuclear weapons.

Moreover, it stretches the imagination to believe that Ronald Reagan would actually preside over this defense cut at a time when the nation is entering serious arms control negotiations with the Soviet Union. Instead, shortly after Gramm/Rudman is passed, and at a moment of heightened tension somewhere in the world, the president will send Congress a message. That message will call upon a Congress to exempt defense from across-the-board cuts in the name of national security. With a simple majority, Congress will then vote to exempt defense.

Once this is done, the entire burden of the budget deficit reduction will come from cutting the nondefense programs and from eliminating cost-of- living adjustments for the middle class and the poor. Nearly all of the reductions would have to come out of the $100 billion that pays for education, the environment, children and other controllable nondefense programs. Even a brief recession in 1987 or 1988 could cause the deficit to mushroom over night, and we would need close to $75 billion to meet the targets of this proposal.

So, within three years, the entire nondefense discretionary budget of the U.S. government would be nearly wiped out by presidential fiat. With Gramm/Rudman attached to the debt limit in the legislative equivalent of the gun fight at the O.K. Corral, Congress will have ceded the authority vested in it by the Constitution and relegated the federal government to the status it held under Herbert Hoover.

Second, this legislation shows Congress at its worst. Gramm/Rudman burst upon the scene little more than eight days ago. The authors and supporters of the amendment continue to modify its provisions daily. One day they say that the entire defense budget is subject to an across-the- board cut. The next day, they say one-third of the defense budget is excluded from the proposal. One day, they say the farm programs are subjected to cuts. The next day the CBO states quite explicitly that farm programs are not covered by this bill. One day Social Security is subjected to cuts. The next day it is sacrosanct. One day the proposal uses CBO numbers. The next day the numbers come from the Office of Management and Budget.

All of this confusion is understandable because no hearings have been held. The bill wasn't even printed until two days after the majority leader insisted we had to vote on it. Gramm/Rudman could very well be an unconstitutional delegation of power, but no constitutional scholar will be able to offer an opinion before it is enacted. It is all too likely that the deliberative branch of Congress may act unwisely in a nine-day rush to judgment.

Third, Gramm/Rudman is a mindless pursuit of a dubious economic objective. It requires the budget to be balanced by 1991. Why 1991? Why not 1994? Why not 1989? Why a balanced budget? The people of this country want spending restraint and deficit reduction. Reducing the deficit is essential, balancing the budget is not. Contrary to the sponsors' favorite analogy, the national government is not similar to a household. Nor is it similar to a state government. The national government has national economic responsibilities that mandate money be spent under certain economic conditions. That is the price of humane government in the 20th century.

The national government also has the responsibility of world leadership. The $9 billion in increased spending on the World Bank that Treasury Secretary James Baker says is essential to resolving the world financial crisis would be impossible under Gramm/Rudman, which would require the president to cut our existing contribution, absent congressional action. Yet unless we take on a leadership role in tackling the mountain of debt now casting a shadow across our economic future, balancing our budget could prove to be an exercise in futility. How could we support Israel and protect our vital interests in the Mideast if we have to make across-the-board budget reductions? There are some things worth spending money on, even if that leaves the budget somewhat unbalanced.

Finally, Gramm/Rudman is posturing at its worst. It is a procedural answer to a substantive problem. But the Senate now has all the procedures it needs to reduce the deficit. What it lacks is the will. A legislator will not cut one dollar from the deficit with a yes vote on Gramm/Rudman. If we truly want to see defense cut 5 percent in real terms, we should vote now to do so. Why must we, in the name of congressional leadership, abdicate to the president our responsibility for setting the nation's priorities? If we believe more revenues are necessary, we should vote a tax bill now. Why must we comfort ourselves with the fiction that, at some point in the distant future, the president will change his mind and accept tax increases or that 66 senators will ram them down his throat then, when they won't now?

The present deficit occurred on Ronald Reagan's watch. The deficits have been predestined since August 1981 when the tax bill was enacted. Congress has cut nondefense spending by $250 billion in the reconciliation acts of 1981 through 1985. Additionally, Congress has reduced the deficit $200 billion with the tax increases of 1982 through 1985. Had Congress not acted, our deficits would be $200 billion larger today.

Instead of once again grappling on a bipartisan basis with the tough decisions, particularly on taxes, Congress appears poised in a moment of irrationality and timidity to give Ronald Reagan the sole power to reorder the priorities of the national government. It will be an action that we will all live to regret.