THE REAGAN Administration has recently taken a few good steps in its professed campaign to fight terrorism by invoking strong economic sanctions against a principal actor in the terrorist scene--Libya and its leader, Moammar Khadafy. By contrast, our European allies appear to have learned nothing from such terrible events as the holiday airport massacres in Rome and Vienna. By their continued refusal to join the United States in concerted sanctions, European governments have doomed their own citizens and untold others to an increase in terrorist violence and a possible upsetting of the balance of power in the Arab world.

The facts about the holiday massacres remain vague, due in no small part to Reagan's promise of "irrefutable evidence" which has not been forthcoming. Nevertheless, it is clear from the events of the last dozen years that three nations--Iran, Syria, and Libya--are principally responsible for Middle Eastern terrorism. Moreover, Libya is the prime culprit in dozens of terrorist attacks, including last month's. While military sanctions would be most likely counterproductive and a violation of international law, economic sanctions against Khadafy's regime are morally justified. And, as happens only rarely in the interdependent world of today, they might actually curb Libya's terrorist activities, providing a practical justification for them as well.

Khadafy's position today is a far cry from the handful of aces he held in 1973. Libya's foreign exchange reserves are dangerously low, and part of Khadafy's claim to power has always been a lavish spending of the nation's petrowealth. Libya's dependence on foreign capital and technical expertise is also critical. Undermining Khadafy's economic position now by shutting him out of Western markets and investments may be just as good as killing him outright; increasing unrest in Libya caused by escalating hardship might produce the same result. If he fears such an outcome, he might make overtures to Western governments promising to stop his terrorist activities. At the very least, Khadafy might curb his actions in the hope of avoiding more severe reprisals.

EUROPEAN GOVERNMENTS remain deaf to all this reasoning. They seem to prefer continued strong ties to the "hard-line" Arab states and favor leaving the role of "terrorism policeman" to the United States. But the time may come when Americans balk at this burden, and the time may also come when Europeans find themselves extremely vulnerable to more than just terrorism. Continued appeasement of men like Khadafy entails many risks, not the least of which is the strengthening of radical hands in the Arab balance of power.

It is particularly disappointing that European governments have taken this "business-as-usual" stance now. The current world oil glut has created a buyers' market in which plenty of oil producing nations would be eager to take away Libya's European market share. And all Western economies have cultivated diverse supply sources and improved conservation measures, making them even less dependent on imported crude. True, some European nations have strong economic ties to Libya that go beyond the realm of the petroleum industry; fully breaking these ties would cause considerable economic dislocation. But the price is worth paying to undermine Khadafy, especially since any relations with such a volatile nation are insecure at best.

Now is the time to turn the economic screws, when Libya has overspent its petrodollars and lost some of its oil market share, when Europe and the U.S. are strong. Europe should no longer subsidize Moammar Khadafy's near-insane drive for power. Our major allies fear the economic and military power of Palestinian fringe groups and the radical Arab states so much, and want to maintain their economic ties so badly, that their regional foreign policy has been nearly paralyzed. This is cause not just for disappointment that a golden opportunity is being lost, but for alarm that men like Khadafy see no end to their blank check for violence.