Washington — Zbigniew Brzezinski, former President Jimmy Carter's national security adviser, says that this weekend's ``summit'' in Iceland between President Reagan and Soviet leader Mikhail Gorbachev could have one of four possible results: A ``cosmetic'' outcome -- some limited accommodation on strategic arms or medium-range missiles in Europe that, by creating the false impression of a major breakthrough in US-Soviet relations, would be ``strategically harmless but politically misleading.''
A ``concessionary'' outcome -- an arms deal that would give the Soviet Union a limited strategic advantage while ignoring such issues as the Soviet occupation of Afghanistan.
A ``strategically stabilizing'' outcome -- a mutually advantageous interim agreement setting arms reduction targets, such as limiting the total number of nuclear warheads but allowing each side the freedom to ``mix'' its systems within that limit.
A ``counter-Glassboro'' outcome -- a concession in principle by Mr. Gorbachev that a ``prudent mix'' of limited missile-defense systems, combined with limits on offensive weapons, would provide the most stable basis for future US-Soviet arms competition. At the 1967 summit in Glassboro, N.J., President Lyndon Johnson and Defense Secretary Robert McNamara did just the opposite, convincing Soviet Prime Minister Alexei Kosygin that a ballistic missile defense system would be destabilizing.
Over breakfast with reporters, Dr. Brzezinski said, ``If Reagan could use Iceland to stand Glassboro on its head, I think he would accomplish the greatest [success].''
Brzezinski says the increased accuracy of missile warheads since 1967, making it possible to target smaller military sites as well as urban population centers, makes some commitment to strategic defense necessary.
Convincing Gorbachev to go along will not be easy, Brzezinski concedes. But he says that by making it clear that the US will step up its own research efforts, with or without the Soviets, it could be possible to ``stand Glassboro on its head'' in Iceland.
The former Carter official says he backs a Reagan plan for a two-year ``expansive phase'' of the 1972 Anti-Ballistic Missile treaty, followed by the treaty's abrogation in order to provide for a``post ABM regime'' allowing deployment of missile defenses. The alternative, says Brzezinski, is a ``technological race that the Soviets can't win.''
On another key issue likely to be raised in Iceland, Brzezinski says the US should be doing more to ``convince the Soviets that [their occupation of] Afghanistan really matters.''
``More could be done to sustain the resistance,'' he says. ``More should be done to keep the issue in the forefront of public attention.''
Brzezinski says the US objective should not be to``humiliate'' the Soviets in Afghanistan. He says a neutral Afghanistan, policed for a time by Muslim forces from countries friendly to the Soviet Union, like Algeria and Syria, would be ``a very good outcome'' for the US.