President Nicolás Maduro of Venezuela had become a pariah among fellow Latin American leaders as his beleaguered country staggered toward dictatorship. But a threat by President Trump to use the American military against Mr. Maduro’s government has united those leaders in a different direction: demanding that the United States keep out of the region’s affairs.
“The possibility of a military intervention shouldn’t even be considered,” Juan Manuel Santos, Colombia’s president, said on Sunday during a visit by Vice President Mike Pence to the region. “America is a continent of peace. It is the land of peace.”
Mr. Santos’s response to Mr. Trump’s remarks — echoed by many other Latin American leaders in recent days — could endanger a fragile alliance against what many fear is the first dictatorship to emerge in the region in decades, analysts say.
“Threatening military action undermines the strongest Latin American consensus in support of democracy that I have seen since the end of the Pinochet regime,” said Mark L. Schneider, an adviser at the Americas program of the Center for Strategic and International Studies, referring to the Chilean military dictatorship led by Augusto Pinochet.
Maintaining that alliance will be a difficult balancing act for Mr. Pence as he tours Latin America this week, with stops in Chile, Panama and Argentina.
Even on the first stage of his trip in Colombia, Mr. Pence shifted tones, urging a “peaceable” solution during a meeting with Mr. Santos on Sunday, then suggesting something tougher when he said the United States would not “stand by while Venezuela collapses into dictatorship” as he met with Venezuelan refugees the next day.
The dispute began last Friday when Mr. Trump, speaking with reporters about an escalating standoff over North Korea’s nuclear weapons, suddenly added Venezuela to countries where he said he was considering military intervention.
“We have many options for Venezuela, including a possible military option if necessary,” the president said.
The remark was immediately seen as bolstering Mr. Maduro domestically, where he, like his predecessor, Hugo Chávez, has long warned of United States coup plots and invasions. But it has also left Latin Americans in a difficult position, forced to choose between one country accused of dictatorship and another being called an empire — or to simply condemn both.
Peru, which has taken some of the toughest stands in the region against Venezuela, issued a statement on Saturday condemning possible use of force, and Mexico said the crisis could not be resolved with soldiers. Brazil said renouncing violence was the “basis of democratic cohabitation.” And human rights groups in Venezuela rejected Mr. Trump’s threat.
Much of the reaction may have to do with history. Many of the countries now rejecting Mr. Trump’s use of military force were themselves invaded by the United States, which once famously regarded the region as “America’s backyard.” Panama, one of the countries on Mr. Pence’s visit, was invaded in 1989 when President George Bush toppled its dictator, Manuel Noriega.
“An often ugly history of U.S. interventions is vividly remembered in Latin America — even as we in the U.S. have forgotten,” said Shannon O’Neil, a fellow at the Council on Foreign Relations specializing in Latin America.
Under President Barack Obama, however, Washington aimed to get past the conflicts by building wider consensus over regional disputes. In 2009, after the Honduran military removed the leftist president Manuel Zelaya from power in a midnight coup, the United States joined other countries in trying to broker — albeit unsuccessfully — a deal for his return.
In 2014, there was more success when Mr. Obama said he would restore relations with Cuba after a half century of Cold War conflict that was a point of contention among many Latin American nations. The diplomatic thaw left much of the region warming to Washington for the first time in years.
Then came the crisis in Venezuela. For more than two years, stagnant oil prices and years of economic mismanagement had left the country short of food and basic medicines. In April, people took to the streets demanding Mr. Maduro’s removal, leading to clashes that have left more than 120 dead.
During Mr. Obama’s last days in office, his administration saw a chance to build consensus through diplomacy, joining an effort by the Organization of American States, a regional diplomacy group, to pressure Venezuela through opening an investigation that could lead to suspension. In March, the United States and more than a dozen other nations publicly urged the country to release political prisoners and hold new elections.
But Mr. Trump’s White House was pursuing a more aggressive path on its own.
In February, the Treasury Department issued sanctions against the Venezuelan vice president, Tareck El Aissami, accusing him of being a drug kingpin. As Mr. Maduro orchestrated a vote to establish a new ruling body on July 30, the White House blacklisted judges and sanctioned more officials; after the vote was held, Mr. Maduro was sanctioned personally, leaving him one of four heads of state to be blacklisted that way.
On Friday came Mr. Trump’s military threat.
While few expected Mr. Trump to actually order an attack, much of the damage was already done for American diplomacy, analysts said.
“Trump’s comments appeared to be, as usual, a sudden outburst that was not thought through,” said Riordan Roett, who heads the Latin American studies program at Johns Hopkins University.
He added that those supporting the leftist movement founded by Mr. Chávez were ultimately the winners.
“It puts the U.S. in the position of the ‘bully’ not unlike the warmongering over North Korea,” he said. “This is a God given gift to the Chavistas.”