For over 50 years, the United States did not have full diplomatic relations with Cuba. The reason was justified: Cuba’s hostility to the United States and often to some of its own citizens.

But the strategy didn’t work. In fact, it may have backfired by allowing Fidel and Raul Castro to scapegoat the United States for the Communist regime’s litany of failures.

This page welcomed President Obama’s announcement that the United States would soon resume full diplomatic relations with Cuba and that it would open an embassy in Havana.

On the same day, the United States released three remaining Cuban prisoners, while Cuba released American Alan Gross and a Cuban who was an agent for U.S. intelligence. Cuba also pledged to free 53 political prisoners.

Among other changes, the U.S. government will loosen restrictions on remittances, banking and travel. Cuba will allow more Internet access.

What Obama cannot do is lift the U.S. trade embargo. That would take an act of Congress, and the sharp criticism from many Republicans — and some Democrats — makes it unlikely that Capitol Hill will capitalize on this moment anytime soon.

Many congressional critics believe Obama’s move cost the United States leverage. But the embargo itself is considerable leverage.

Most important, the Cuban people may now be more likely to look inward for answers on why the Western Hemisphere’s freedoms have not yet reached, and improved, their lives.

The purpose of diplomacy is to enhance U.S. interests. With rare exceptions, that can be better facilitated by engagement, even if a country’s government is repressive. The United States has diplomatic relations with scores of repressive regimes, including many allies.

Diplomatic disengagement from Cuba not only didn’t work, it strained relations with several regional allies. The support of these nations is important on hemispheric issues and also to build support in international institutions like the United Nations that are designed to pressure regimes — including Cuba’s — to reform.

There should be no illusions about the Cuban government’s need to reform. Its human rights record is shameful, its economic policies have often impoverished and it has often allied itself with other rogue regimes.

Those policies, however, weren’t reason enough to continue the diplomatic freeze. Instead, they made it more important for the United States to engage Cuba and take America’s compelling case directly to its people.