Tuesday proved to be an eventful day for Washington and Havana as the U.S. Treasury and Commerce departments loosened export restrictions against the United States' southeastern neighbor. But while the move will be good for cross-border trade, that trade is only part of a much bigger story. Cuba's transition from a Cold War relic to a vibrant Caribbean economy will be fraught with risks, and how Havana handles them will determine whether U.S. investors choose to do business there or turn to other competitors in the region....