Reading the Cuban Liberty and Democratic Solidarity (LIBERTAD) Act of 1996 better know as "la ley del embargo" is a much better source of information as to the purpose of the law and how to lift the embargo
Here are some excerpts;
SEC. 3. PURPOSES.
The purposes of this Act are-
- to assist the Cuban people in regaining their freedom and prosperity, as well as in joining the community of democratic countries that are flourishing in the Western Hemisphere
- to provide for the continued national security of the United States in the face of continuing threats from the Castro government of terrorism, theft of property from United States nationals by the Castro government, and the political manipulation by the Castro government of the desire of Cubans to escape that results in mass migration to the United States;
- to encourage the holding of free and fair democratic elections in Cuba, conducted under the supervision of internationally recognized observers;
- to provide a policy framework for United States support to the Cuban people in response to the formation of a transition government or a democratically elected government in Cuba; and
- to protect United States nationals against confiscatory takings and the wrongful trafficking in property confiscated by the Castro regime.
SEC. 204. TERMINATION OF THE ECONOMIC EMBARGO OF CUBA.
(a) PRESIDENTIAL ACTIONS- Upon submitting a determination to the appropriate congressional committees under section 203(c)(1) that a transition government in Cuba is in power, the President, after consultation with the Congress, is authorized to take steps to suspend the economic embargo of Cuba and to suspend the right of action created in section 302 with respect to actions thereafter filed against the Cuban Government, to the extent that such steps contribute to a stable foundation for a democratically elected government in Cuba.
SEC. 205. REQUIREMENTS AND FACTORS FOR DETERMINING A TRANSITION GOVERNMENT
REQUIREMENTS- For the purposes of this Act, a transition government in Cuba is a government that-
- has legalized all political activity;
- has released all political prisoners and allowed for investigations of Cuban prisons by appropriate international human rights organizations
- has made public commitments to organizing free and fair elections for a new government--\
- with the participation of multiple independent political parties that have full access to the media on an equal basis, including (in the case of radio, television, or other telecommunications media) in terms of allotments of time for such access and the times of day such allotments are given; and
- to be conducted under the supervision of internationally recognized observers, such as the Organization of American States, the United Nations, and other election monitors;
Makes public commitments to and is making demonstrable progress in--
(A) establishing an independent judiciary;
(

respecting internationally recognized human rights and basic freedoms as set forth in the Universal Declaration of Human Rights, to which Cuba is a signatory nation
(C) allowing the establishment of independent trade unions as set forth in conventions 87 and 98 of the International Labor Organization, and allowing the establishment of independent social, economic, and political associations.
Everything is well detailed as to how to lift the embargo. What or who is preventing it?