IN the post-Desert Storm era the US military is being drawn into a larger long-term role in the Middle East, even as American units get ready to come home from other parts of the world.Ever since President Carter declared the oil supplies of the Persian Gulf a vital US interest, the Pentagon has been seeking freer access to the region. Before Saddam Hussein invaded Kuwait, most Arab nations felt such a visible, permanent relationship with United States armed forces unthinkable. Now many judge it a necessity. Thus, the new military alliance between the US and Kuwait, signed last week, represents a major turning point for the American presence in the region. Details of the 10-year pact weren't disclosed, but officials said it doesn't call for permanent stationing of US troops on Kuwaiti soil. Instead, it allows port access by Navy vessels, joint military training, and prepositioning of weapons and other military equipment. Most important is its symbolism: It makes explicit a US commitment that was only implicit before the war. "Our presence is linked to stability there. Our presence indicates the resolve of the American people," says one knowledgeable military official. Ironically, before Desert Storm, there weren't any US troops committed solely to possible Middle East roles. The military assets of Central Command, the part of the military responsible for the region, were units earmarked first for possible use in Europe. Now the US role in Europe is being cut drastically, with at least half the American troops based there sure to come home, while the Middle East has risen to the top of the Pentagon's list of concerns. Not that there are plans for a permanent US military base in the Gulf, similar to the decades-old US reservations in Germany. US officials insist they aren't talking to anybody about leaving large numbers of troops behind. But they say other military agreements similar to that signed with Kuwait are in the works with Bahrain, Oman, Qatar, and the United Arab Emirates. The US is also negotiating with Saudi Arabia itself. In the immediate aftermath of the war Pentagon officials said privately they wanted to leave at least a division's worth of tanks and other weapons at King Khalid Military City in the Saudi desert as a hedge against future Iraqi adverturism. But talks continue to be stalled over the exact nature of control and ownership of any pre-positioned equipment. "We're looking at it. We're not sure" what's going to happen now, says a Pentagon official. The reasons for the new Arab flexibility are two: In a general sense, the experience of Desert Storm has greatly enhanced US credibility and military prestige in the region; and specifically, everyone is still worried about Saddam. The Iraqi leader was shorn of much military power, but what remains is considerable. At least two full Republican Guard divisions escaped destruction, numbering, between them, some 25,000 troops. Perhaps more important, many experts believe that Saddam will continue to try to see what he can get away with and will continue to drag his heels and resist attempts to get him to comply with war-ending UN resolutions. Saddam doesn't appear to be chastened or willing to go along easily. "He's never going to rol l over and say 'OK,' " says Greg Weaver, a senior military analyst at SAIC Corp. That's the context of President Bush's threat last week to send more US warplanes to the Gulf to escort UN inspectors. The threat was mostly a political message, as there are already enough fighters in the Gulf to accomplish such a mission. But it appears designed to tell Saddam that despite the uproar in the Soviet Union the White House hasn't forgotten about him. Since then the White House has been at pains to play down chances for a Desert Storm Two. And having already once stopped short of marching to Baghdad and removing Saddam at the point of a gun, the US might find it hard to rally its allies for anything beyond defensive action. "Unless the Iraqis do something extraordinarily stupid, such as shoot down a UN helicopter or kill a UN inspector, we can do a great deal of posturing, but it would be extraordinarily difficult from a political view to countenance US use of force," says Alan Sabrosky, international studies expert at Rhodes College in Memphis and a former Army War College professor. Much US military power remains in the Persian Gulf. The largest contingent is the Navy's, with 16,000 personnel concentrated in two aircraft carrier battle groups. The Air Force has about 60 attack planes left in Kuwait and Saudi Arabia, including F-117 Stealth fighters. About 11,000 Army troops remain, though most are members of logistics units. The 3,700-man 11th Armored Cavalry Regiment, sent to Kuwait in June to serve watchman duty, is now in the process of being rotated back to its German home base. It is being replaced by a task force of about 1,500 infantry troops from other units based in Germany.