"Were it not for the declaration of martial law, the substantiation of that announcement in mid-winter would have signified not only economic but also biological catastrophe. No grand issues and dilemmas may be studied without their historical backgrounds in separation from the realities of a given moment. A historian seated in the tranquility of archives and libraries can allow his thoughts to wander in various directions. Basing on continually supplemented sources, he knows today what took place in the past. But a politician active at that time knew only what was happening at a given moment. And he also had to take into account that which could take place. A historian enjoys the comfort of delivering evaluations which have no practical effects."