THE freeing of American hostage David Jacobsen in Lebanon is welcome obviously for his own sake and for that of his family. But it is welcome, too, for the promise it holds that the remaining 17 people held hostage or missing in Lebanon - French, American, British, Irish, and other nationalities - will sooner or later be released. Gaining the release of those still thought to be alive, however, may be no easy matter. The hostage-taking aspect of terrorism has grown more convoluted the past three years or so, with governments like Syria and Iran and not just terrorist organizations getting involved.
Still, there must be a way, or a series of ways, through the frustrating maze of obstacles to the kidnap victims' release. They are innocents unjustly abducted into political or armed confrontations to which they are no party. On the principle of their innocence alone, their freedom can be sought by governments and by individuals like Terry Waite, the envoy of the archbishop of Canterbury who played a role in Mr. Jacobsen's release.
Abiding by an absolute outward position of ``no deal'' becomes difficult for governments like Washington, London, or Paris, when faced with the obligation to do all they can through secret channels to explore the prospects of their citizens' freedom. The conditions for Jacobsen's release are not yet known - for instance, whether it will be followed by any release of Muslim extremists held by Kuwait after carrying out bomb attacks on US and French targets, or some other concession in return for Iran's apparent pressure on Jacobsen's Islamic Jihad captors. It is unclear whether the release came with Syrian assistance or, as some analysts suggest, despite Syria's irritation over Iranian influence in a part of the Middle East Syria considers its own turf. But the pattern of securing cooperation among Western and Middle East governments, and the intervention of individuals or third-party groups in dealing with the shadowy extremists, for now appears necessary.
Some analysts see the possibility of further diffusion of Middle East terrorism into Western Europe. Working against this trend, they also say, is pressure on the Soviet Union - if it wants to seek an arms control agreement with the United States - to keep its client states like Syria from getting out of hand in the sponsorship or implicit sanctioning of terrorist activities.
Washington, London, and Paris differ on what to do about Syria, which apparently both abets terrorist enterprises and extends its services as an intermediary for resolving disputes. With the Soviet Union over its shoulder and with an armed force of some stature, Syria does not offer the same sitting duck for retaliation as does Libya.
Further, there is the eventual hope for resolution of the Arab dispute with Israel, particularly over Israel's occupation and settlement of the West Bank. Too heavy an investment now in assailing Syria could frustrate what must be the primary goal of Westerners' Middle East policy, securing an Arab-Israeli peace. It is the absence of that peace, together with Arab world rivalries, that eventuates in terrorist ferment and abduction of innocents.
Washington can do far more than it is doing on the Mideast peace side. But the Reagan administration is correct to affirm that it is working without pause to secure, through whatever channel it can, the release of all remaining captives in Lebanon. This is no easy task. Meanwhile, each incremental success - like Jacobsen's release - should be welcomed.