Anya Landau French has a good comparison of the sanction policies against Burma and Cuba. Key point:
Unlike the maze of Congressionally-mandated sanctions against Cuba enacted over the last several decades, the Burma sanctions were designed to expire unless proponents make a compelling case to renew them. The sanctions only last a year, unless Congress passes a joint resolution to renew them another year. Imminent expiration of the sanctions means that Congress actually monitors and evaluates the effectiveness of its policy toward Burma every year, instead of leaving the sanctions in place indefinitely at the whim of the single most interested member or members of Congress, as in the case of the Cuba embargo… But because the Cuba sanctions are open-ended and lack meaningful oversight, Cuban officials insist they can have little confidence that the U.S. will actually take significant steps to improve the relationship even if Cuba does.
This problem was in part created by and is certainly amplified by the fact that the embargo is not designed in any meaningful sense to change the behavior of the government of Cuba. Rather, it is designed to meet the demands of a small but vocal and strategically located US voting constituency.
I was very hopeful about Obama’s Cuba policy before the election. As in many other things, Congressional intransigence and the administration’s unwillingness to press the issue have meant that gains have been measured. As French points out, however, Cuba has seen a good deal of meaningful economic and even political reform over the past few years, even in absence of any US moderation.