Jordan's King Hussein made a one-day trip to Baghdad today to shore up Iraqi strongman Saddam Hussein's campaign against Iran, and said it was "possible" that Jordan would give Iraq military assistance.

While he avoided making an unqualified offer of direct military assistance, the king said in response to questions that military help was "possible, particularly since the question involves our existence as a nation."

In the face of threats by Iranian leader Ayatollah Ruhollah Khomeini to act against Islamic nations that assist the Iraqi effort with military or propaganda support, the Jordanian monarch declared that Amman is "not neutral" in the Persian Gulf conflict.

As if to underscore this, Jordan continued to funnel top-priority cargo to Iraq and otherwise aid Baghdad indirectly. The key port of Aqaba, for instance, has been practically turned over to the Iraqis as a pipeline of supplies shipped through the Red Sea.

[Reports reaching Washington, meanwhile, said Iraq flew three planeloads of wounded soldiers to amman Sunday and that Jordan has begun sending truck fuel to Iraq from a refinery north of Amman.]

While the king's Cabinet ministers fell into line publicly behind his stand, there were signs that some senior Jordanian officials were having second thoughts about just how far out in front of the rest of the Arab world Jordan should be in backing Iraq.

Moreover, some leaders of Jordan's business and banking community, whose instinct for financial survival apparently transcends their fervor for Arab unity, were known to be quietly questioning the wisdom of Jordan's getting too deeply drawn into the Iraqi camp when the outcome of the war is far from certain.

"There are a lot of survivors here, and while you will never hear them say it publicly, they are beginning to wonder why do we have to be so far in the front of everyone else in this war. They're saying, 'Iran is a big country, and the Iraqis haven't done very well against Iran's supposedly nonexistent Air Force,'" an informed source said today.

Fuelng these concerns, sources said, is the knowledge that continued Jordanian backing of Iraq at the level the king is pursuing will exacerbate tensions with neighboring Syria, which is still showing empathy for Iran in its uphill struggle with Iraq.

Conservative Islamic leaders, uncomfortable with the prospect of Jordan being involved in a war against any Moslem nation, also have begun to question the level of King Hussein's involvement in the Iraqi-Iranian conflict. Further some Palestinians, who supported Khomeini's revolution and feel a kinship toward Iran, are starting to view the gulf war as weakening the united Arab front against Israel.

Furthermore, there is a certain irony in Hussein's strong support of Iraq, since he is a member of the Hashemite dynasty that was overthrown by Iraq's Baathist leadership and once stood in succession to the Iraqi throne.

All of the tentative and beneath-the-surface second thoughts about the king's support of Iraq have been overwhelmed by the government's unceasing pro-Iraqi propanganda campaign. This campaign is most noticeable on state-controlled television, where long segments of Iraqi-produced newsreels are shown nightly. They are usually followed by accounts praising King Hussein's steadfastness behind Saddam Hussein.

"JTV [Jordanian television] has turned into Baghdad TV, but it doesn't take long to realize that there aren't any films of ethnic Arabs in Khuzestan greeting the Iraqi soldiers with flowers," one observer remarked.

Informed sources said it is certain that the views of some of the doubters have been brought to the attention of the king, either directly or through intermediaries. But one observer remarked, "There are certain things no one can convince the king of, and this is one of them."

King Hussein's one-day trip to Baghdad came as no surprise to observers here, since he had been known to be anxious to go before now, but had been discouraged by Saddam Hussein for reasons of personal security. In the early days of the conflict, the king sent his top Cabinet ministers to Iraq, and he has been in daily telephone contact with Saddam Hussein, as well as King Khalid of Saudia Arabia and other Arab leaders.

"He believes if the Arabs stand united with Iraq, it will be a message to Iran that they cannot be adventurous in the gulf. Also, it will lessen the chances the United States will have to intervene, and, therefore, lessen the likelihood of superpower confrontation here," an informed Western diplomatic source said.

While observers here are convinced that the king's moves have been motivated by intense feelings of pan-Arabism, they are equally certain that he will go to great lengths to avoid direct military involvement unless it is absolutely unavoidable.

Answering questions by reporters accompanying Austrian Chancellor Bruno Kreisky on his trip to Jordan on the eve of the monarch's trip to Baghdad, King Hussein said it was possible that he might approve aid to Iraq, although he noted that Jordan has no defense agreement with Iraq, and that Saddam Hussein had not asked for military aid. a

Jordan already has let Iraq use a remote air base in the northeast as a haven for military transport aircraft, in addition to letting Baghdad use the Aqaba port.

A maritime source who had just returned from Aqaba said that first priority was being given to unoading ships that are backed up waiting to be unloaded. The Iraq-bound goods are transported overland.

Shipping sources said there was no discernible evidence of armaments being unloaded, although they noted that Iraq's war effort would be seriously impaired in any case if the pipeline of goods from Aqaba was not open.

Beyond the king's desire to contain Iranian influence in the gulf, observers here see a broader strategy being implemented, that of forming a coalition of conservative states -- with the acquiesence of Iraq -- to develop an alternative to the Camp David peace process to unite the Arabs. Such a coalition, diplomatic sources believe, would be spearheaded by Jordan, Saudia Arabia and Morocco.

The coalition, initially drawn together at King Hussein's behest in a united stand behind Iraq, would attempt to supplant both the Camp David process and the embryonic European intiative toward reaching a solution to the Palestinian problem.

Inevitably, observers here believe, it would put Syrian Predsident Hafez Assad under enormous pressure to go along with the scheme. King Hussein's efforts to rally a united Arab stand behind Iraq against Iran, it is felt, is only the beginning of the squeeze that Assad is likely to feel in the months ahead.