NOWHERE else but in Prague.As central and eastern European countries shift uncertainly from totalitarian to democratic modes, debates in these countries are heating up over what is acceptable political expression. Old rules are changing. But what are the tradeoffs to be weighed when trying to establish both openness and the rule of law? Consider, for example, the case of the pink tank in Prague. About a month ago in the middle of the Czechoslovakian capital, a Charles University student named Cerny, in an act sophisticated enough to be both very comical and very serious, painted a Soviet memorial tank pink. The pink tank told the Soviets, who were busy junking their bases and leaving the country, "Don't forget to close the door on your way out." Never mind that the tank was a World War II memorial. The fact that it was a Soviet tank in Prague was enough for Cerny. The symbolic act was taken very seriously by local police, who promptly arrested Cerny under an old law titled Article 202. Ironically, this is the same "disturbing the peace" law that current Czech President Vaclav Havel was arrested on only months before the Velvet Revolution in 1989. Nor did high-ranking Soviet military officials care for the pink tank. The Czech Foreign Ministry was embarrassed and, instead of a measured response, fell over itself in an apology to Moscow. One morning Prague woke up to find the tank painted black, as if to show shame over the previous act. These events, along with sentiments by some officials that Cerny should be prosecuted, set off a storm of public protest. Thirty-five federal assembly members took cans of paint to the tank and repainted it pink. Other acts of political theater, a veritable battle of symbols, followed. The head of a statue of Jan Polach, a student who immolated himself in Wenceslas Square during the 1968 Soviet invasion, was found painted white. In retaliation, a number of students took the stones from the base of the repainted pink tank and made a small memorial nearby to General Vlasev's army. Vlasev was a Soviet defector who ended up fighting the Nazis in Prague and was turned over to the Soviets after the war and promptly exe cuted. Political theater in Prague may seem entertaining to Westerners, but it has come to symbolize in the East a great struggle over changing values, over right and left, and between young and old. What is acceptable as political expression? What is just? What is Czechoslovakia's relationship to the Soviet Union? If nothing else, it is encouraging that such debates are taking place in the open, in newspapers that have sprung up in Prague in the past two years. Democratic debate is essential in building a healthy political culture. Moreover, it is encouraging to note how sophisticated the Prague debate has been. One might expect all former opposition members and dissidents to sympathize with the federal assembly members who got in their licks on the tank. Yet this has not been the case. Czech Prime Minister Tithart said the federal assembly act was "immature." The former underground newspaper Lidovy Nominy opposed the federal assembly act as political grandstanding. Lidovy editor Jan Urban said to this writer: "I support Cerny's ar tistic expression and would support other artists who wanted to paint the tank as often as they wanted. But it is the federal assembly's job to make and amend laws, not to break them." The rule of law is at the heart of democratic structures and institutions. Those in Czechoslovakia and elsewhere who are trying to uphold it are to be applauded. Yet so is Cerny (for reasons of politics and public relations, it now looks doubtful that he will be prosecuted). Both sides are helping to season the young revolution of 1989 and consolidate its gains.