Even though both U.S. businesses and the general population of the United States favor a radical change in U.S. policy toward Cuba, the Obama initiative was limited by the fact that it was all accomplished by White House executive orders. The blockade and travel restrictions are enshrined in laws passed by Congress, which can only be modified or eliminated by new acts of Congress. These laws include the Trading with the Enemy Act, the Torricelli Act (or Cuban Democracy Act), and the Helms-Burton Act (or Cuban Liberty and Democratic Solidarity Act).
http://www.cubaontime.com/us-city-state-legis...ba-policy/