Washington — Off the coast of Lebanon this week, American guns roared. In Washington, President Reagan met with leaders of two of the Middle East nations most friendly to the United States.
But neither the naval gunfire nor the highly publicized proclamations from Washington concerning commitments to the Lebanese government, as well as to a broader peace process, seemed to matter much for the moment.
On the ground in Lebanon, events appeared to be spinning beyond United States control.
The key figure on the ground is Syrian President Hafez Assad. And the key question being asked here is: How far does President Assad intend to push?
Is the Syrian leader driving for total domination or a balance of power in Lebanon? And, finally, how far is his influence - and that of his ally, Iran's Ayatollah Khomeini - likely to spread as a result of Syria's victory in Lebanon?
''The Syrians are 'on a roll,' '' say Washington analysts, who have adopted the language of Las Vegas gamblers to talk about a Syrian winning streak.
The question for the US then becomes not only how to strengthen Lebanon's President Amin Gemayel but also - perhaps most important at this juncture - how to strengthen other Arab nations considered here to be moderate and friendly to the United States.
Whether or not the US goes along with an abrogation of the May 17 Lebanon-Israel agreement matters little at this point, some analysts say. Things have moved beyond the point where a decision to abrogate amounts to much of a bargaining card, they say. Secretary of State George P. Shultz said Wednesday that the US continues to support the agreement.
What King Hussein of Jordan and President Hosni Mubarak of Egypt told President Reagan here this week is that the US could help to stabilize the situation by pushing harder on the Palestinian issue. The essence of their message is that the US should put more pressure on Israel to stop West Bank settlements and halt what looks like a process of de facto annexation of that captured territory. President Mubarak once again called for direct talks between the US and the Palestine Liberation Organization.
No one really expects President Reagan to make any significant moves in this direction in an election year, however, given the power and influence of the friends of Israel in this country who would move against him should he decide to confront Israel.
But the Reagan administration has been looking at limited means of shoring up Egypt, Jordan, and the Gulf states, while making a modest attempt - short of a ''tilt,'' officials say - to help support hard-pressed Iraq politically and economically in its struggle to defend against Iran. Jordan has been promised the first installment of more than 1,600 Stinger, shoulder-held antiaircraft missiles - still far from what it needs to defend against Syria, most analysts say. Egypt is negotiating with the administration over debt relief and its demand for equality with Israel.
Although they disagree on the Palestinian issue, the Americans on the one side, and Jordan and Egypt on the other seem to agree that Syria's current gains in Lebanon could eventually upset the balance of power in the Middle East. But if their public statements are any indication, the Egyptians recognize that the US is eventually going to have to sit down and bargain with the Egyptians' old rivals for Arab leadership, the Syrians.
The Reagan administration has never been entirely clear as to what President Assad has as his ultimate goal beyond an expansion of Syria's influence. It may take a few more battles in Lebanon and many more hours of negotiation to find out.
Anthony H. Cordesman, a former Defense Department official with long experience in the Middle East, sees a danger, meanwhile, that Syria's victory in Lebanon will lead to greater conflict throughout the region.
As Mr. Cordesman views it, the Syrians' recent successes will likely lead the Soviet Union to ''reward'' Syria with the delivery of more advanced weapons, such as air defense systems, thus confronting Israel with a new challenge. But Cordesman also sees a danger that Syrian successes will encourage ''hard line'' regimes - specifically, Iran and Libya - to put greater pressure in the region on Arab regimes friendly to the US.
''There is going to be considerable momentum behind terrorist and subversive elements working with Iran and with Syria,'' said Cordesman, who is international policy editor of the Armed Forces Journal. ''We are also going to face an almost inevitable stepup in the Syrian threat to Jordan.''
Although Cordesman discounts the possibility of any immediate Syrian threat to Israel, he does say that the Israelis are facing a dilemma. If they show restraint, he says, they will face a steady buildup of Syrian strength - along with growing Syrian and Iranian influence in the south of Lebanon.
''They can act extensively now or face a steady erosion in the balance which could eventually threaten Israel,'' said Cordesman.
He does not see a need to increase already high levels of US aid to Israel. He does see a need to ''shore up the American image'' in the Arab world.
The veteran defense analyst argues that levels of military aid to Jordan are far from adequate. He contends that the US could do more to provide debt relief to Egypt. He sees a need to help southern Gulf states create effective naval and air defense systems. And finally, he urges creation of a US-European structure to identify and counter terrorists.