However, some former officials defended the meetings, arguing that something must be done to stem the humanitarian crises set off by Mr. Maduro’s authoritarian leadership, from shortages of food and medicine to the migration of millions of Venezuelans from the country.

“If you don’t like the idea of the U.S. talking to the military, then what do you propose?” said Richard N. Haass, a former top State Department official in the George W. Bush administration who is now the president of the Council on Foreign Relations.

He said that while he did not support a coup, the region should consider a “Latin American coalition of the willing,” an alliance of Venezuela’s neighbors created for a possible regional military intervention, similar to the United States’ invasion of Iraq.

While Latin American leaders loudly condemned remarks by President Trump last year saying there was a “military option” to thwart Mr. Maduro, the reaction to the news that American officials had met with coup plotters was muted this time. Mr. Morales was the only president who came to the defense of Mr. Maduro.

That reflects the growing exasperation with Mr. Maduro’s government, some experts say.

“There is so little sympathy now,” said Michael Shifter, the president of the Inter-American Dialogue, a Washington policy forum. While Mr. Shifter does not support a coup either, he said comparisons to the overthrow in Chile of Salvador Allende in 1973 by Gen. Augusto Pinochet, who became a military dictator, were unfounded, given the humanitarian crisis Mr. Maduro had caused.

There are signs that the Trump administration may harden its stance toward Mr. Maduro, one of the few sitting presidents currently under sanctions imposed by the United States. The White House is expected to name Mauricio Claver-Carone to head Latin America affairs at the National Security Council.

Mr. Claver-Carone is considered a conservative hard-liner on Cuba and was involved in tightening American sanctions against Venezuelan officials. He would report to John Bolton, who came to lead the N.S.C. in April and is also seen as more hawkish than his predecessor.