Nicaraguan President Daniel Ortega and first lady Rosario Murillo, now his running mate. (Esteban Felix/Associated Press)

FROM 1936 to 1979, Nicaragua was ruled by a corrupt dynasty, the Somoza family, that enjoyed U.S. backing until it grew so vicious and venal that a national revolutionary movement rose up against it. Now one of the former leaders of that rebellion, Daniel Ortega, is about to inaugurate his own dynasty. On Sunday, following gross ma­nipu­la­tion of the constitution and electoral system, Mr. Ortega will preside over his reelection as president, as well as the installation of his wife, Rosario Murillo, as vice president. Mr. Ortega, who is 70 years old and reported to be ailing, will thus ensure that the presidency remains in his family; his children are waiting in the wings.

The United States earned enormous discredit in Latin America for its backing of the Somozas but apparently learned nothing: With little more than a few grumbles, the Obama administration has tolerated and worked with the new Ortega regime. This, despite the fact that Mr. Ortega, a close ally of Fidel Castro, has been an adversary of the United States throughout his life and lately has begun purchasing weapons from Russia while granting a shadowy Chinese business executive rights to build a canal across the country.

The few news reports on the upcoming ballot retail a conventional wisdom that Mr. Ortega is popular enough to win without fraud. But that conclusion disregards the historical fact that the caudillo lost every democratic election held between 1990 and 2006 — when he corruptly reengineered the system to allow victory with a minority of the vote. That Mr. Ortega was not confident of his popular support was evident in June, when he arranged for his leading opponent to be removed as head of his political party and replaced with someone of Mr. Ortega’s choosing; 16 members of the party who objected to the coup were then expelled from the National Assembly.

The State Department shrugs off these and other abuses with rote expressions of “concern.” If there is reason for this other than sheer lassitude, it would be Mr. Ortega’s pragmatic embrace of the Central American Free Trade Agreement, which has allowed Nicaragua to nourish textile and other firms exporting to the United States; and his cooperation with anti-narcotics programs. Once a socialist, Mr. Ortega lately has made a virtue of self-interested flexibility, contriving to combine the benefits of American free trade and loans from U.S.-backed multilateral institutions with his opaque dealings with the would-be Chinese canal builder and heavy subsidies from Venezuela, another anti-American bastion.

Congress may put an end to this free ride. A bill passed without opposition by the House in September would mandate U.S. opposition to new multilateral loans to Nicaragua until it “is taking effective steps to hold free, fair and transparent elections.” That could curtail what is now a flow of about $250 million annually — and give Mr. Ortega reason to cooperate seriously with an initiative to restore democracy by the Organization of American States. Opponents protest that this sanction would hurt ordinary Nicaraguans more than Mr. Ortega. However, like the Obama administration, they offer no alternative other than rhetorical scoldings of the caudillo. Which raises the question: Would that have been the right response to the Somozas?