The tightening screws of U.S. policy against travel to Cuba loosened a little this week when the Treasury Department, which enforces the Cuba embargo, extended by one month the time in which Americans legally visiting Cuba had to return to the U.S. or face fines of $55,000. The deadline is now July 31 rather than June 30. The June 30 deadline still applies, however, to educational trips to Cuba, which now must be at least 10 weeks long to qualify. Most educational trips to Cuba are shorter, with few universities able to take groups over for entire semesters. The net result of the new regulation is to stop most educational travel to Cuba.