President Saddam Hussein of Iraq cashing in on carefully cultivated relations with the conservative Arab monarchies that not so long ago viewed his radical Baathist government and its Soviet ties with distaste and suspicion. Because of the buildup in these links -- and in part because of Arab-Persian enmity reaching back for centuries -- the conservative Arab states are rallying behind Saddam Hussein with suprising vigor as his Iraqi forces penetrate deeper into neighboring Iran.

The role call is steadily growing: Saudia Arabia, Jordan, Morocco, Qatar, Kuwait, United Arab Emirates and North Yemen. All have gone along, in varying degrees, with Saddam Hussein's successful efforts to assume a larger role not only in the Middle East but also among the world's nonaligned nations.

Among Saddam Hussein's backers in the week-old Iraqi-Iranian war, none has been as active as Jordan's King Hussein, who himself has long cherished a role in engineering the kind of Arab unity that has eluded this part of the world for years.

Seemingly at the expense of his own ambition, King Hussein has been rallying support for Saddam Hussein like a political convention floor manager, enlisting commitments from potential supporters and carefully reaffirming pledges made before.

If the moderate 45-year-old monarch is uncomfortable in the role of sealing Saddam Hussein's claim to regional leadership, he shows no evidence of it. A Jordanian official who has always gone to great lengths to magnify the king's leadership position among conservative Arab states practically beamed with pride for Saddam Hussein when he said: "He will come out definitely as a stronger figure in [Arab] national leadership. If he wins this war, it will be the first time in 50 years that there was a successful Arab [military] operation."

Traditionally in the Middle East, whenever cataclysmic events shake the wobbly foundations of pan-Arabism, the telephone is the instrument used to avert a complete unraveling of common interests, and the Iranian-Iraqi war is no exception.

King Hussein, according to his aides, has been assiduously dialing rulers of the Middle East, urging a unified stand against Iran and behind Saddam Hussein.

At least once a day, and often several times, according to an aide, the king has been calling leaders, including King Khalid of Saudia Arabia, President Hafez Assad of Syria, Sheik Jaber Ahmad Sabah of Kuwait, Sheik Zayed ibn Sultan Nahayan of the United Arab Emirates, Sheik Khalifah ibn Hamad Thani of Qatar and North Yemen's President Ali Abdullah Saleh.

Some calls have produced demonstrable results, including overt backing of the Iraqi cause. Others have led to more restrained results, such as Syria toning down its attacks on Iraq. But all of them seem to reflect the king's persuasiveness with his fellow Arab leaders.

When fighting between Iran and Iraq first broke out, there was something less than unanimity among Arabs over whom to support. Some conservative Arab states showed signs of fence sitting, partly out of fear that taking sides would spread instability, and partly because some states, particularly in the Persian Gulf, have large populations of Shiite Moslems, as does Iran.

But King Hussein took up the cause of Arab unity with a vengeance and in a highly public fashion after the war broke out. State-controlled television, for example, has been carrying long propagandistic defenses of Iraq's position in the Shatt-al-Arab waterway dispute. The Arabic press here also has been praising the king's role in Drumming up support for Saddam Hussein. h

When asked why the king, whose moderation has long contrasted sharply with Saddam Hussein's rule, took it upon himself to muster the conservative monarchies behind Iraq, an official said:

"First, he felt Iraq was right and that Arab land was at stake. Second, he believes all of this teach Israel a lesson that if the Arab world gives up on trying to negotiate a peace settlement, we can put together a united military stand. It is an illustration. If the Arabs can unite against the Persians, they can unite against Israel."

Then, perhaps getting closer to the point, the aide added, "Also, the king has proved, at least to the Iraqis, that we were the first and the strongest supporters of Iraq, and Iraq will not forget it for a long time."

Jordan is heavily dependent on foreign aid, receiving two-thirds of its annual $1.6 billion budget in aid. It gets $1.25 billion alone a year from Saudi Arabia, Iraq., Qatar and Kuwait. Of that Iraq contributes more than 12 percent, and in addition picks up shares pledged, but never paid, by Libya and Algeria.

Moreover, Iraq is spending $300 million in many development projects in Jordan, including a highway from Basra to the port of Aqaba, and has offered further assistance, such as providing water from the Euphrates River to northeast Jordan, and building a university in the south.

At the same time, Jordanian officials believe, the king is not sacrificing any regional political advantage he may have gained when President Anwar Sadat of Egypt became a black sheep in the Middle East by signing a peace treaty with Israel.

"On the contrary, he is creating a brighter image for himself among Arabs as spokesman for unity, coordination and interaction," an official said.

This image emerges, significantly, as construction worker put the finishing touches on a new convention hall in the hills of residential Amman that will house an Arab summit conference planned next month. King Hussein is known to be eager to make the conference a showcase of Arab unity, and it is clear that his anxiety over the possibility of the Iraqi-Iranian war scuttling this dream at least in part motivated his efforts to enlist support for Saddam Hussein's campaign against Iran.