Iraq's offer this week to sell oil to anyone, including the United States, for $21 a barrel - the pre-invasion price and half the present cost - is a sign of desperation, a signal that the embargo is working. It also is an obvious effort to undercut current international isolation of Iraq. That must not be allowed to happen.

So far, there seems to be no rush to respond to Saddam Hussein's offer of inexpensive oil any more than there was to his offer a few weeks ago of free oil to Third World nations hurt by the international embargo. Of course, with a naval blockade in place, oil shipments at any price are impossible unless there is a falling out among major the powers. That does not seem likely at the moment.Imposing sanctions is a lengthy and frustrating experience. It does not offer a quick and satisfying solution to the problem and, inevitably, there are cries for more direct action.

Certainly, it is difficult to stand by month after month while torture, murder and other atrocities are committed against the people of Kuwait, while the country is looted and systematically dismantled, and while Americans and other hostages are held and international law flouted.

Calls for military action against Iraq if Saddam does not pull back from Kuwait are growing. British Prime Minister Margaret Thatcher has been outspoken in this regard. Even United Nations General Secretary-General Javier Perez de Cuellar said this week that if sanctions do not work, then military action against Iraq would be legitimate.

Yet there is no reason to rush into action. The embargo appears to be holding up reasonably well. Only Jordan - which pays lip service to the U.N.-sponsored embargo - is violating the sanctions in practice, shipping a steady flow of goods into Iraq.

Even with that limited hole in the embargo, the sanctions are having an effect. It is simply going to take more time for the squeeze to become painfully effective. What Saddam might do if the embargo begins to strangle Iraq is unclear. The pressure might force a peaceful withdrawal or he could decide to fight rather than starve. Either way, Iraq is weaker with each passing month.

In the meantime, although the global economy has been disrupted, the world is not suffering a serious oil shortage. Other suppliers are making up nearly all the shortfall caused by the loss of Iraq and Kuwait oil production. The world can afford to wait.