Neither engagement nor isolation have worked.

By MARIA WERLAU

The ascendancy of Raúl Castro to Cuba's presidency has fueled expectations of reform in the 50-year-old dictatorship. Next week, President Barack Obama will be pressed on the issue at the Summit of the Americas in Trinidad-Tobago.

It is a good time to acknowledge that neither the U.S. embargo nor engagement by the rest of the world have helped Cubans attain their rights. Sanctions, though ethically justified, can't work unilaterally; treating Cuba as a normal partner is immoral and counterproductive. A new unified approach is needed.

Just as the oppressed people of South Africa, Chile, and other tyrannies received international support, finding an effective approach to the Cuba problem is a shared duty. It is also in everyone's interest. A democratic, stable and prosperous Cuba would cease threatening the security of the region, slow the flow of Cuban refugees and provide better trade and business opportunities.

If the U.S. president understands totalitarianism better than his hemispheric counterparts, he will remind them that at the Ibero-American Summit in 1996 Fidel Castro signed the Viña del Mar Declaration pledging to support democratic pluralism. He has consistently ignored all such international agreements. Now Trinidad summiteers should jointly call Cuba's bluff.

What is needed is a policy of comprehensive conditional engagement. Measures chosen from the menu of possible policy measures should not depend on cooperation from Cuba, should be flexible if Cuba responds, and should factor in sanctions of increasing firmness. Developing a multilateral effort would extend the responsibility for the democratization of Cuba to the international community, where it belongs.

The Castro brothers have long fed delusions that engagement will bring change, no matter that legions of reform-touting emissaries have consistently come away empty-handed.

Ineffective efforts to end Cuba's isolation are manifest in the tourism industry. Over two million tourists from all over the world travel there annually, including U.S.-based visitors (an estimated 1.3 million in the past 10 years). Yet strict laws still govern labor relations with the foreign sector. Workers are selected for political allegiance and must be hired from a state enterprise that retains over 90% of their wages plus all tips. The state still owns the tourist industry, so billions in revenues continue to pour straight into its coffers or into overseas bank accounts.

The U.S. has also engaged Cuba commercially. Sales of medical and agricultural products have been long exempt from the embargo. But Cubans are forbidden from importing those goods or owning businesses to distribute or sell them. Instead, the ruling elite enjoys privileged access to food, consumption goods and premiere medical services, while the population does without. Many pharmacies and hospitals lack even aspirin. The obligatory food ration book is pitiful and provides insufficient calories.

The latest, much hyped, "reforms" consist primarily of allowing citizens to buy cell phones and enter tourist facilities. But the cost of a cell phone or one hotel night exceeds the annual wage of the average worker ($16 a month). The government launched a novel, island-wide "dialogue," but it was quickly stopped when the regime's flaws surfaced too visibly. Finally, a recent purge inside the regime left the new dictator-in-chief in firm command.

Twenty years after the collapse of the Soviet Union and "the world opening to Cuba," Cubans are no more free. The state still decides where people can work, study and live, and it owns all mass media and means of production. The Internet, travel abroad, and all organizations not affiliated with the Communist Party or the state are barred.

No dialogue is possible with a leadership bent on survival sustained by an entrenched repressive apparatus. Among its favored tools are surveillance, removal from jobs and housing, forced exile, and arbitrary detention.

Cuba is ranked by Freedom House as one of the world's most repressive countries. Over 200 political prisoners are being held along with tens of thousands incarcerated for "economic crimes" such as resorting to the black market for sustenance that ruinous central planning cannot provide. Prison conditions are barbaric. The death toll includes scores murdered while fleeing the island or lost at sea. The forgotten Guantánamo -- on the Cuban side -- hosts not only ghastly prisons, but also the equivalent of two Berlin Walls around the U.S. Naval Base to prevent escapes -- one by land and one in the water, on the bay itself.

A ruthless tyranny has lasted far too long. It demands a sensible and unified response.

Ms. Werlau is a consultant in New Jersey and co-founder of the nonprofit project, Cuba Archive.