They slept that night in peace. The danger, they felt, had ended. Their democratic revolution would live. The Russians would not come in. As they slept, the chief of Czechoslovakia's secret police, who was scheduled to lose his job within a few days, arrived at Prague's new airport - to secure the field, he explained, for the arrival of an important Russian delegation. Within minutes, Czech and Soviet agents ringed the field, and airborne troops landed. At 1:00 a.m., the people of Prague awakened to the blaring of taxi horns and to news they could not at first believe.