PAKISTAN IS THE LATEST of the countries along the Soviet Union's long Asian frontier -- after Iran and Turkey (Afghanistan is special) -- to be faced with internal unrest on a scale raising geopolitical tremors. Their distinctive features aside, all three have been Western-oriented places whose struggles to modernize have raised popular expectations, caused social and cultural dislocations, and provided an opening for a revival of Islamic currents that throw a shadow over the country's future. Pakistan has also had to cope with the trauma of losing its eastern wing (now Bangladesh), and with the political aftereffects of that, including the crisis that threatens to devour it now.

The president, Gen. Mohammed Zia, ousted the elected president, Zulfiqar Ali Bhutto, by coup in 1977 and put him on trial for ordering the murder of a political rival. The Supreme Court has just confirmed the trial court's guilty verdict, and Gen. Zia must decide what to do. Gen. Zia lacks both the legitimacy of Mr. Bhutto, who was elected, and Mr. Bhutto's popularity, although he seems to be trying to compensate for the latter by riding the Islamic tide. He has a problem. If he hangs Mr. Bhutto, the politician's constituency may tear the country apart. If he grants clemency, Mr. Bhutto, as vindictive as he is brilliant, may ignite a campaign that will have the same effect.

Long a friend, the United States retains a strong interest in Pakistan's stability -- the more so that some other pro-American ramparts seem to be crumbling. Faced with many claimants, Jimmy Carter has offered what economic and military support he could, though not enough to make Pakistanis feel that he is nearly as devoted to their development and security as Republican presidents have been in the past. In the Bhutto crisis, Mr. Carter had to find a stance satisfying this country's traditional friendship, its concern for stability and its humanitarianism. It is the last factor that seems most responsible for the advice he finally offered Gen. Zia. He suggested that a decision for clemency would earn him the esteem of right-minded people everywhere.

We found this suggestion not merely patronizing but quite possibly counterproductive. It risks being read as gratuitous intervention in Pakistani internal affairs at a time when Gen. Zia is looking for something very different from the United States. What obviously concerns Gen. Zia more is the overall stance the administration takes in the region. Taking note of the turmoil, he asked rather plaintively the other day that Mr. Carter "act like the president of a superpower." In the context, it was clear he meant that the United States should give firmer support to its friends. The administration has been trying to do that in a variety of ways, local and regional. But whether the support held out to Pakistan will significantly diminish its gathering storm remains, unfortunately, very much a question.