THE Soviet Union's nationalities problems are Mikhail Gorbachev's equivalent of crabgrass. He might try pull them out in one place, but they'll pop up elsewhere. The decision to moderate Moscow's economic embargo of Lithuania does credit to Mr. Gorbachev's political pragmatism. The Baltic states are not going to be scared away from independence. But their leaders, too, are pragmatists, as the Lithuanian government's move to suspend its republic's declaration of independence shows. The Balts appreciate the continuing importance of ties to the Soviet Union, their sole supplier of critical resources like oil and gas.
This nationalities question is now at least tending toward resolution.
That can't be said about the increasingly bloody conflict in Central Asia between Uzbeks and Kirghiz. Underlying the tension are profound economic woes. Unemployment is proliferating as population is exploding. Thirty years ago Uzbekistan had 8 million people; now it has almost 20 million. Homelessness is epidemic, as are health problems from environmental degradation. Islamic fundamentalism could yet become a potent political force in the area.
Only economic betterment and efforts to cleanse the environment can ease the unrest in Central Asia. But these remedies aren't in sight, given Moscow's political flux.
Then there's the continuing, volatile confrontation between Armenia and Azerbaijan. Azerbaijan refuses to loosen its grip on the disputed territory of Nagorno Karabakh, which is under its administration but is Armenian in population and culture. The Soviet troops sent in to quell fighting between the two peoples are a hated presence to both sides. Leaders in Moscow - and outside the Soviet Union - need to recognize the human rights issues involved and enourage talks and compromise.
But Gorbachev's attention, and most of the rest of the world's, is riveted elsewhere.
Moves toward sovereignty in the largest Soviet republic, Russia, are meanwhile revising agendas for everyone. As often happens, the crabgrass is becoming the lawn.