THE MOST frequent charge made against President Carter is that he is indecisive, but the charge misses the mark. His indecisiveness has been, if anything, beneficial to the nation, at least where the large questions of foreign policy are concerned. The real problems come when the president begins thinking that he must be forceful.

Things weren't going too badly, for example, while the president was responding to the Iranian situation. Voicing protests, impounding Iranian assets, appealing to the World Court, rounding up Iranian students, sending the shah to Panama -- all were well within the range of Carter's reputation for tentativeness.

But then, when the Soviets invaded Afghanistan, the president became a changed man. The White House reported that he was reading studies of how former Oval Office tenants had responded to crises. Announcing that he now realized he could not trust the Kremlin, Carter suddenly came out firing real decisions. Nearly all of them wrong.

Bang -- an embargo on shipments of agricultural products to Russia, then a limit on Russian fishing rights in U.S. waters. The trouble, as the experts in these areas will tell you, is that neither action is likely to have any lasting effect on the Soviet Union.

Bang -- a ban on shipments of high-technology equipment, such as computers and oil drilling machinery, to Russia. Unfortunately, if there is truth to U.S. intelligence reports that Russia's domestic oil supplies are running low, cutting off oil technology and equipment seems exceedingly unwise. It could hasten the day when, in need of oil, Russia might take military action to control Mideast supplies -- a course which Henry Kissinger, not long ago, accepted as possible for the United States to take.

Bang -- declarations that U.S. military power in the Persian Gulf and Indian Ocean would be strengthened, that we would resume and increase arms shipments to Pakistan, that we should revive draft registration (though, true to his earlier incarnation, Carter said, on the one hand, that he didn't think a draft itself would be needed and, on the other hand, that we would use military force if necessary to protect our interests in the region).

Rather than frightening the Kremlin, all this seems to be most worrisome to our allies in Western Europe, who have not endorsed any intervention in the area. (Nor have they indicated any great willingness to reduce trade with Russia or its satellite countries.)

Similarly, neither Saudi Arabia nor the emirates along the Persian Gulf have rejoiced over the president's offer to protect them, and India has protested our proposed military aid to Pakistan. That, of course, is not too surprising, since U.S. military aid to Pakistan in the past has been used against India, at least when it has not been used against other Pakistanis.

Finally, the big bang -- boycotting the summer Olympics in Moscow. The case for doing this and for moving the Olympics to another site borders on the ridiculous. There is little evidence that holding the 1936 Olympics in Berlin advanced the cause of Nazism, and there is scarcely any reason to believe that staying away from Moscow will damage communism.

As with most other instances of the president's troubling decisiveness, this step appears to be aimed more at venting American frustration and satisfying the American psyche -- to say nothing of boosting certain political polls -- than at accomplishing anything else in the world. It should also be noted that nobody moved to keep U.S. athletes from participating in the 1968 or 1972 Olympics, although in those years the United States was involved first in what was called an "invasion" of Vietnam and then, under President Nixon, in an "incursion" into Cambodia. Possibly if Brezhnev had had a Rafshoon as a media adviser in those years, he might have protested the American presence at the games.

More serious than particular substantive mistakes by the president is his evident misunderstanding or misconception of the role America should play as a world power, how that role should be played, and especially how U.S. relations with Russia should be conducted.

Charles de Gaulle observed that a country's foreign policy, if that land wants to be a force in the world, had to be a projection of the nation's internal strength and dynamism, and that when foreign policy began to feed back and threaten to destroy the integral character of the nation, it was time to change or abandon the policy. Applying this rule to French involvement in Algeria, de Gaulle saw France as threatened and withdrew. American foreign policy, too, must be a projection of the ideas of American democracy, consistent with both the principles of that democracy and with the procedures and institutions of its system.

The "balance of power" theory, advanced by Henry Kissinger and Zbigniew Brzezinski, both schooled in the history of the Austro-Hungarian Empire and in the principles that preserved it for a time, would have been rejected out of hand by Thomas Jefferson. President Carter, though, seems attracted to it, despite the fact that recent experimentation by the United States in supporting undemocratic governments has not worked very well. Among earlier examples are the Batista government in Cuba, the series of military juntas in Greece, the Somoza regime in Nicaragua and, more recently, the shah in Iran. The test of democracy is always both substantive and procedural.

Of more immediate concern than the threat of "balance of power" presidential politics is the evident failure of the president, in dealing with the Russian invasion of Afghanistan, to distinguish between what is more and less important.

De Gaulle observed of the Russian suppression of the Czechs in 1968 that the incident was serious but that it was a distraction on the way to "detente." The Soviet invasion of Afghanistan did require a measured response from the United States. Protest, participation in U.N. condemnation of the action, offers to help countries that might be threatened by further military action, some movement of U.S. military strength into the area -- all of these were warranted.

The response should have been shaped to fit the limited significance of the Afghanistan invasion. It should not have been allowed to interfere, except peripherally, in the two major areas of potential U.S.-Soviet accommodation and understanding: one of nuclear confrontation and the other of commerce and culture, including trade and sports.

In the State of the Union message of Jan. 23, the president said, "Now, as during the last three and a half decades, the relationship between the United States and the Soviet Union is the most critical factor in determining whether the world will live in peace or be engulfed in global conflict." And he added that "preventing nuclear war is the foremost responsibility of the two superpowers."

These words are at best only marginally related to what may come of some of the president's decisions stirred by the Afghanistan invasion. SALT II has been shelved and the mobile missile program improved. The Russians have responded by testing new missiles. Meanwhile, as the price of conventional military support from Pakistan and possibly from India, the president of Pakistan has indicated that he will take the $400 million in military aid (which he has termed "peanuts") but with no strings attached.

This certainly suggests that he intends to proceed with development of the nuclear bomb, which he has labeled the "Islamic bomb." He makes a strong religious point, for there are thousands of Christian bombs under U.S. control and thousands of "atheistic bombs" and undoubtedly a few "Orthodox bombs" in the Russian arsenal. There is the reported "Judaic bomb" in Israel, a "Hindu bomb" in India and what might be called a "Buddhist bomb" in China. If the Japanese were allowed to proceed, they could quickly produce a "Shinto bomb," thus putting all the major religions of the world under the protection of both the gods and the nuclear umbrella.

By the end of his term, if he continues to be decisive, President Carter may have the country close to a military involvement in the Middle East, which might qualify as what Secretary of Defense Brown defines as a "half war," a term developed during the Pentagon reign of Robert McNamara and used to identify the war in Vietnam. We may have opened the way to further proliferation of such weapons by the two great proliferators, the Soviet Union and the United States.

Having achieved all this, or at least having helped set the stage for it happening, he could then run for reelection on the slogan: "He kept us out of the Olympics."