The church's calls for an end to the embargo, which the United States imposed in 1962, are not peculiar to its Cuba policy, and are not concessions granted in negotiations with the communist government. They follow from established principles of Catholic social teaching, which have been applied to a variety of countries over the years.

"The Holy See maintains that the embargo is something for which the people suffer the consequences and which does not reach the aim of promoting the greater good," said Jesuit Father Federico Lombardi, the Vatican spokesman. "The people suffer; therefore, the Holy See does not believe it is a measure that is positive or helpful."

"The position of the Holy See has been repeated many times," Father Lombardi told reporters March 16. "It's not a mystery."

The Vatican's position on economic embargoes -- not just the embargo against Cuba, but even briefer embargoes against Iraq and Libya -- has been repeated many times and is explained in the official Compendium of the Social Doctrine of the Church.

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The church recognizes international sanctions as a legitimate and potentially effective means of trying to pressure a government to change its ways when it threatens peace or oppresses its people.

However, in a way that is both reasonable and motivated by concern for people, especially a society's weakest members, classic Catholic social doctrine places conditions on the use of sanctions.

The purpose of sanctions "must be clearly defined" and regularly evaluated by the international community "as to their effectiveness and their real impact on the civilian population," the compendium said.

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"Economic sanctions in particular are an instrument to be used with great discernment and must be subjected to strict legal and ethical criteria," it said. The compendium also said that "an economic embargo must be of limited duration and cannot be justified when the resulting effects are indiscriminate." In other words, if the nation's rulers are the target, it's not right that only the country's powerless suffer because of the embargo.

Pope Benedict, like Blessed John Paul II before him, is expected both to call for an end to the U.S. embargo and for increasing freedom in Cuba, especially in the area of religious freedom.

In fact, Pope Benedict did just that in late 2009 when he welcomed a new Cuban ambassador to the Vatican. He said he knew Cubans were suffering from the global economic crisis, which "together with the devastating effects of natural disasters and the economic embargo particularly strikes poorer people and their families."

At the same time, the Pope said the real key to progress in Cuba is to "put the person and his rights, his material and spiritual well-being, at the center of concern. Indeed, the primary capital to be safeguarded and saved is man, the whole person."

The church is prepared to help and already shows its dedication to the Cuban people through its educational and charitable work, "although small in size," the Pope said.

He added that he hoped "concrete signs of openness to the exercise of religious freedom would continue to multiply as they have in recent years."

In 1995, three years before he went to Cuba where he made similar points, Pope John Paul laid out the ethical criteria for evaluating economic embargoes.

In a speech to diplomats serving at the Vatican, he said economic embargoes must be used "with great discernment and must be subject to rigid juridical and ethical criteria. It is an instrument of pressure to urge governments that have broken the international code of good conduct to rethink their choices."

"Still, in a certain sense, it is also an act of force and, as several current cases demonstrate, it inflicts great privations on the population of the countries that are its object," the Pope said.

Pope John Paul said the matter was not simply theoretical for him. "I often receive requests for help from people who are the victims of this isolation and indigence."

"I want to remind you diplomats that before imposing such measures, the eventual humanitarian consequences of sanctions must be taken into account" and the possible harm sanctions can cause a population must be weighed against "the evil one wants to remedy," he told them.