Leading the way was the Obama administration, which responded to the crisis, and to the pleas of prospective adoptive parents and the lawmakers assisting them, by lifting visa requirements for children in the process of being adopted by Americans.

Although initially planned as a short-term, small-scale evacuation, the rescue effort quickly evolved into a baby lift unlike anything since the Vietnam War. It went on for months; fell briefly under the cloud of scandal involving 10 Baptist missionaries who improperly took custody of 33 children; ignited tensions between the United States and child protection organizations; and swept up about 1,150 Haitian children, more than were adopted by American families in the previous three years, according to interviews with government officials, adoption agencies and child advocacy groups.

Among the first to get out of Haiti were Beechestore and Rosecarline. “It’s definitely a miracle,” Mrs. Stroot said of their arrival here, “because this wasn’t going to happen.”

Under a sparingly used immigration program, called humanitarian parole, adoptions were expedited regardless of whether children were in peril, and without the screening required to make sure they had not been improperly separated from their relatives or placed in homes that could not adequately care for them.

Some Haitian orphanages were nearly emptied, even though they had not been affected by the quake or licensed to handle adoptions. Children were released without legal documents showing they were orphans and without regard for evidence suggesting fraud. In at least one case, two siblings were evacuated even though American authorities had determined through DNA tests that the man who had given them to an orphanage was not a relative.