(FORTUNE Magazine) – -- Where do the 134 U.S. corporations that have gone into business in the Soviet Union -- Dresser Industries, E.I. Du Pont, Honeywell, McDonald's, PepsiCo, and Polaroid among them -- stand now? The country's economy is ''a lunatic asylum,'' says economist Nikolai Shmelev -- and Mikhail Gorbachev's success in winning a five-year presidency carries no real guarantees. Joint ventures have increased 100% since July 1989. The start-up investments -- over $200 million -- are minimal. More worrying is Gorbachev's political survival. If conservatives regain power, says Jan Vanous, research director at PlanEcon, a Washington, D.C., consulting firm, ''we would retaliate with increased defense spending and trade restrictions.'' Like most business leaders, Charles Hugel, chairman of the U.S. subsidiary of Asea Brown Boveri, thinks Gorbachev will survive. Besides, ''Any successor will have the same problems.''