It was a rare diplomatic gamble when the three leaders of Latin America’s largest democracies inserted themselves into the high-stakes standoff between Venezuela’s Nicolas Maduro and his opponents over who won the country’s presidential election.

Dubbed the three amigos — all dyed-in-the-wool leftists who have been friendly with Maduro — the presidents of Brazil, Colombia and Mexico broke from decades of hands-off diplomacy toward Venezuela and their own reluctance to meddle in a neighbor’s sovereign affairs in a region where U.S. military interventions during the Cold War still generate resentment.

But some experts say the peacemaking effort is losing steam before barely getting off the ground.