SADDAM HUSSEIN, who began his career in the secretive and violent world of Iraqi politics as a teenage gunman, has changed the course of Arab and global politics with his invasion of Kuwait. The Arab world and the international community face a regional power that is willing to use brute force, backed up by chemical weapons, against all comers. If they fail to block the Iraqi dictator's drive for regional supremacy, other ambitious rulers will be encouraged to follow in his footsteps.

Saddam, as the Iraqi leader is universally known in the Middle East, struck at his small, defenseless neighbor confident that other Arab countries were too weak to stop him, and that the only regional powers capable of opposing him -- Iran and Israel -- would not come to Kuwait's defense. He could also be sure that in the new climate of Soviet-American cooperation, the superpowers would not react with direct military action.

In military terms, the Iraqi invasion is little more than a particularly vicious mugging of a rich little old lady who has been openly stalked and taunted by the neighborhood bully for months while everyone else looked the other way.

It is the failure of any other country to deter Saddam that makes the Kuwait invasion a watershed in regional and global politics. The surprise and inaction of the United States and its Arab allies in the face of the invasion stands in stark contrast to what previous American presidents and Arab rulers would have felt compelled to do in similar circumstances.

Eisenhower sent U.S. Marines to Lebanon in 1958 in far less threatening circumstances. Nixon and Kissinger encouraged Israel to protect Jordan's King Hussein from Syria and radical Palestinian forces in 1970, and called a nuclear alert during the 1973 Arab-Israeli war. Carter and Reagan both built up a Rapid Deployment Force to keep Persian Gulf oil in friendly hands.

But Saddam has met no meaningful opposition in the past year from George Bush as he has coerced other Arab leaders into silence or support for his ambitions to rule the Middle East. Jordan's King Hussein, once a close American ally and the quintessential survivor of Middle Eastern politics, caught the trend early by forming an alliance with Baghdad. He felt he could no longer rely on Washington, the king tells visitors to Amman. That is a feeling that now risks becoming universal in the Arab World as the Iraqis digest Kuwait.

Saddam, now 53, has relied on violence or the threat of violence as his primary instrument of achieving what he wants throughout his political career, which began in 1959 when he sprayed a dozen machine gun bullets into the limousine of President Abdel Karim Kassim in an unsuccessful assassination attempt.

Saddam, a law student, was part of a three-man hit team. He fled the scene on foot and hailed a taxi. Rather than visit a doctor and risk exposure, he cut a revolver bullet out of his leg with a penknife and escaped abroad. He lived in Damascus and Cairo before returning to Baghdad in 1963 after army officers belonging to his Baathist party killed Kassim.

But the officers lost power nine months later and Saddam was arrested after a daylong shootout with police. He escaped from jail in 1965 and was pardoned a year later by the government, which made the mistake of seeing him as a youthful hothead who could be redeemed. Others have been making that mistake about Saddam ever since.

Despite the lip service he pays to the Arab Socialist creed of the Baath party, power for himself and for Iraq is the only ideology that Saddam has consistently pursued. By 1972 he had risen to the number two position in the Baathist regime and supervised the abrupt nationalization of the British-owned Iraq Petroleum Co. The takeover, Saddam told me during an interview in Baghdad three years later, was a decisive event in his political career. After a brief period of bluster, Britain accepted the nationalization and set about doing business with Iraq again.

Our conversation occurred shortly after Iran and the United States had halted their support for Kurdish rebels who rose against Baghdad in 1973. This betrayal strengthened Saddam in his conviction that the West would eventually fold in a confrontation. But he also showed signs of ideological flexibility in that meeting. He expressed hopes of normalizing relations with the United States, hopes that soared when the Shah of Iran fell and the fundamentalist Shiite regime of Ayatollah Ruhollah Khomeini came to power in Tehran.

The presence of the bitterly anti-American regime in Tehran has colored U.S.-Iraqi relations, making Washington more reluctant to oppose Saddam's adventures and relentless pursuit of chemical and nuclear weapons than it should have been. Encouraged by assessments from Washington and Iranian exiles that the Khomeini regime would quickly collapse, Saddam invaded Iran in 1980, launching an eight-year military stalemate that devastated Iraq's economy but built up a combat-hardened army of one million men.

With the disappearance of the Shah of Iran, who once offered protection to the small Gulf oil producers against Iraq, and the destruction of Iran's military machine, Iraq emerged from the war as a hungry lion among a herd of gazelles who had lost their historic protectors. The other non-Arab power of the region, Israel, confirmed last week through its inaction that it had no interest in providing protection for a small Arab state that had faithfully bankrolled the Palestine Liberation Organization. The Kuwaiti ruling family that Saddam deposed has been as committed to the destruction of Israel as has the Iraqi strongman, if not more so.

Iraq's invasion is in fact a bonus for Israel. The Arabs have denounced the Israeli occupation of Arab land since 1967 as illegal, immoral and a danger to international peace. Now that an Arab army occupies Arab land, the force of that argument disappears.

The Iraqi invasion is a death blow to the already reeling force of Arab nationalism as it was conceived and propagated by the Egyptian revolutionaries who overthrew King Farouk in 1948 and set about reinventing the Arab world. Saddam does not replace Gamal Abdel Nasser so much as he buries what was left of Nasser's pan-Arab philosophy. With the invasion, Saddam has shown with brutal clarity that force has become the common denominator of Arab politics.

Saddam dreams of returning Iraq to the dominant position it occupied in ancient times as Mesopotamia. Other Arab leaders will become his satraps in this vision. "There are no borders between Arab countries," Saddam pointedly told a Kuwaiti envoy last winter. His arch rival, Syria's Hafez al-Assad, his army tied down in Lebanon, did not move a muscle as Iraqi troops took Kuwait's oil wells.

Nor did Saudi Arabia, despite the massive and controversial purchases of U.S. arms such as F-15s and AWACs aircraft in recent years. The inability of the Saudi-U.S. security partnership to contain Iraq will add to the sense in the Middle East that the direct strong role the United States once played in the region is a thing of the past.

In the Arab world this risks becoming a self-fulfilling prophecy. Since World War II, the United States has seemed to Arabs to be the source of mythic power, working its will in the region with ease. This has brought resentment because of the Israeli-American alliance, but it has also brought the United States respect and cooperation. These will now disappear if Washington does not find effective ways to counter Saddam's appropriation of a country seen throughout the region as an American friend and economic ally.

The Bush administration also carries the burden of showing that its appeasement of Saddam, in hopes that he could be rehabilitated, did not help persuade him he could get away with the Kuwaiti invasion and threaten Saudi Arabia's borders.

The administration has chosen to emphasize the need for Arab action and collective action by the international community to make Iraq withdraw from Kuwait and refrain from attacking Saudi Arabia. But neither course will work without strong, effective American leadership committed to the removal of Saddam.

Neither Saudi Arabia nor Turkey is likely to risk direct confrontation with Iraq by unilaterally cutting off the Iraqi oil pipelines that pass through their territory. But both could be made to observe an embargo and naval quarantine enforced by an international force. Iraq's desperate economic condition, which helped trigger the invasion of Kuwait, would quickly worsen under a blockade.

The war with Iran saddled Iraq with an estimated $80 billion in debt to Arab and Western countries and an undisclosed amount to Iraq's main arms supplier, the Soviet Union. (With Soviet help a rapidly wasting asset, Saddam lost little by angering Moscow with the move against Kuwait.) But the invasion of Kuwait will turn out to offer Saddam little immediate help, a reality that he may not have taken into account. The Iraqis will have found only small change on hand in Kuwait, which has systematically invested the lion's share of its oil earnings in the West.

According to Arab banking sources, Kuwait's commercial banks normally keep only about $7 billion on hand in gold and foreign reserves, and may have moved much of this to other countries in the Gulf as tension increased. Most of the nearly $200 billion in assets held by Kuwait's government and the small private sector is tied up in investments in the United States, Britain and Spain or in non-performing assets in Third World countries. These can be protected by an effective international freeze on Kuwaiti assets.

The American strategy must aim at turning the Kuwaiti occupation into a new burden on Iraq's already strained economy. Saddam has bullied his way to the center of world attention and concern, a phenomenal accomplishment for this ex-street tough. But Napoleon's law that dictators can do anything with bayonets except sit on them applies to Saddam too. The United States bears special responsibility to prove that.

Jim Hoagland is chief foreign correspondent and associate editor of The Washington Post.