Some Republicans and Cuban-American lawmakers are criticizing President Obama for shaking President Raúl Castro’s hand at the memorial service for Nelson Mandela. Their reaction to a gesture of common courtesy should come as no surprise given Washington’s senseless commitment to a failed 50-year policy toward Cuba.

This page has long called for an end to America’s embargo, which has strengthened the hand of Mr. Castro, his brother Fidel and other hard-liners who have used it as an excuse for their disastrous misrule in Havana. And it has hurt the Cuban people whom we claim to want to help.

Supporters of the embargo, including Cuban-American lawmakers like Senator Marco Rubio, Republican of Florida, have argued that it gives the United States leverage and should not be removed until democracy returns to the island. The fact that the Castros remain firmly in charge in Havana more than a half-century after President John F. Kennedy instituted the restrictions against Cuba shows how effective that idea is.

Mr. Obama took some tentative steps to ease the embargo in 2009 by allowing Cuban-Americans to visit and send remittances to the island. He also cleared the way for telecommunications companies to establish licensing deals in Cuba. But the administration has not pushed publicly for any significant changes since then.