MAYBE it was an intimation of the long Russian winter ahead that made him pull back. Maybe it was the prospect of the big speech he is to deliver Nov. 7 on the 70th anniversary of the Bolshevik Revolution, a draft of which had provoked resistance within the party Central Committee. Maybe his reservations about the American Strategic Defense Initiative run deeper than Washington had calculated. Maybe he wants to sow a little discord among NATO allies who differ on arms control strategy, or to exploit White House preoccupation with financial crisis. Whatever the cause or causes, Mikhail Gorbachev has balked at setting a date for his long-anticipated visit to the United States. The official centerpiece of the visit was to be the signing of an arms accord on midrange missiles. Mr. Gorbachev says the American SDI program still gives him pause.
The White House is right not to react overmuch to Gorbachev's second thoughts. The administration had appeared too eager for a summit spectacular, for reasons that may have more to do with securing Mr. Reagan's place in history than in nailing down an arms accord.
Arms control is a two-track process. There is the hard-slogging effort behind closed doors to shape agreements and resolve differences. And there is the broader political effort in which domestic and allied constituencies are prepared for agreements. Certain time constraints are natural to the American system: If a midrange missile accord is not set by winter, before the election cycle cranks up in earnest, another two years could pass before Washington can take a new fix on the subject. Momentum toward a 50 percent cut in strategic weapons would be slowed.
The Soviet political system has its own dynamic. Perhaps a US summit and an intermediate-arms accord should have been kept separate from the outset. Arms control is the work of a generation of leaders, and should not be crowded by political opportunism.