The United States has imposed sanctions to cut off Venezuela’s oil revenues and against banks, including one in Russia. It has canceled the visas of officials in the Maduro government and talked to nations about taking in others who might seek asylum or a safe haven. And it maintains that “all options are on the table” — even while assuring allies that military intervention, of the kind that the United States has had a long and ugly history of carrying out in Latin America, is not really being considered.

But Mr. Maduro remains, to the surprise of many in the Trump administration.

Now, Mr. Trump faces the same problem that his predecessor, Barack Obama, confronted after saying in 2012 that President Bashar al-Assad of Syria would be severely punished if he used chemical weapons — the dangers of making a tough declaration that the United States is unwilling or unable to enforce.

“It’s a tough situation with no clear end in sight, and momentum appears to be moving in the wrong direction,” said Fernando Cutz, a former senior White House official on Latin America policy in the Obama and Trump administrations.

The move to vacate the United States Embassy in Caracas was a significant setback for the Trump administration. American officials had previously vowed to keep diplomats in Venezuela to legitimize Juan Guaidó, the opposition leader who declared himself the interim president in January.

The decision was difficult for Mr. Pompeo to explain.

The diplomats in Caracas “have done great work,” Mr. Pompeo said in a television interview on Tuesday in Houston, where he was attending an energy conference. “But it was time for them to come back. Their security is always paramount. And it’s just gotten very difficult.”