Thousands of Central Americans fleeing oppression and violence in their homelands are huddled along the U.S.-Mexican border. So far, they have been denied asylum and may well be forced to return to an uncertain destiny.Eighty years ago a similar crisis arose when more than 900 European refugees were not allowed to land in Florida or Canada and were returned to Europe. They were the passengers on the MS St. Louis, “the ship of the damned.”By 1938, the world knew that almost all of Europe’s Jews — and …