Gorbachev's Summer

WITH populist Boris Yeltsin looming behind him, Mikhail Gorbachev needs victories on the world scene and at home. He must show at the crucial July 2 Communist Party Congress that his vision for both military security, and economic recovery, are working. He needs to avoid a split party. Both President Bush and British Prime Minister Margaret Thatcher, by her upcoming high-profile trip to the USSR, are committed to helping Mr. Gorbachev in the weeks before the Congress.

By agreeing to pay for Soviet troops in East Germany, and through longer-range assistance that may include construction of housing for returning Soviet troops inside the USSR, West Germany is also making things easier for the Soviet leader.

Western leaders are supporting what seems to be Gorbachev's home strategy: that, if the Soviet Union stays on his course, investment and concessions from a peaceable West are forthcoming.

And not only the West. Gorbachev's historic meeting in San Francisco with South Korea's Roh Tae Woo may yield significant investment from that country - in exchange for diplomacy leading to a warming of North and South Korean relations.

Gorbachev's task is formidable. Part of Mr. Yeltsin's appeal, apart from people's affinity with his native ``Russianness,'' is his effectiveness as a liberal critic of perestroika. Yeltsin himself is a man without a plan, but that doesn't matter in the short term.

At the Party Congress Gorbachev also needs to accommodate conservatives. Their constituency, a reportedly growing ``silent majority'' of ordinary Russian traditionalists, are still not used to the idea of NATO and a unified Germany joining up.

Gorbachev has used his reported political weakness as a device in dealing with Mr. Bush. Gorbachev was unable, for example, to agree to a comprehensive US nine-point plan for a reunified Germany in NATO. Nor were agreements reached about conventional force reductions (CFE) in Europe. The US and several European states link CFE to progress in the CSCE talks - the 35-nation, pan-European alliance Gorbachev is uses as a model for the new Europe. A December CSCE summit is still scheduled.

CSCE may offer a fine future. But in the interim, NATO is the only security game in town. Presumably, Gorbachev needs to get past this Party Congress in order to make deals involving Germany and troop cuts. When he does, he should accept Bush's generous NATO plan and agree to troop reductions. Keeping things uncertain in order to get the best deal won't score points for Gorbachev past this summer. The West needs stability too.