But the government stood its ground Monday, saying it would not allow the head of the commission, Iván Velásquez, a Colombian citizen, to return. Instead the government said the United Nations, which appointed Velásquez to oversee the International Commission Against Impunity in Guatemala, should pick someone else to head the mission.

The announcement not only defied the constitutional court’s unanimous ruling late Sunday, but it was also a challenge to United Nations Secretary General Antonio Guterres. In a rebuke to the Guatemalan government, Guterres had said at the beginning of the month that Velásquez would remain at the head of the panel even though he was barred from the country.

At the root of the crisis are a series of corruption investigations by the commission that have rocked the core of Guatemala’s power structure, sending politicians, businessmen and even former presidents to jail.

The commission’s investigations were once helpful to Morales: They helped unearth wrongdoing by his predecessor and contributed to Morales’ surprising victory in 2015. But when an inquiry into illegal campaign financing focused on Morales directly, he made Velásquez persona non-grata and vowed to shut down the commission.

The fracas Monday was the culmination of more than a year of conflict between Velasquez and Morales. At first Morales, whose brother and son are both awaiting trial on corruption charges brought by the commission, tried to expel Velásquez from the country. But the constitutional court, the nation’s top judicial body, deemed the move illegal.

For a while, the matter appeared to be resolved. But Morales said on Aug. 31 that he would not renew the commission’s mandate. Four days later, the government also barred Vélasquez, who has been the head of the commission since 2013, from returning to the country.

To most legal experts, that violated the spirit of the earlier decision. And indeed, when the court took it up again Sunday night, it unanimously ruled that any attempt to block the entry of the panel’s commissioner into the country was illegal.

But because the ruling did not mention Velasquez by name, the government decided to impose its own interpretation. The Interior Minister, Enrique Degenhart, was categorical Monday, declaring, “It is important to set the condition that the Colombian citizen Ivan Velasquez Gomez, will not enter” Guatemala.

Instead, Foreign Minister Sandra Jovel said Guatemala had asked Guterres to come up with a list of acceptable replacement candidates within 48 hours.

Polls show that the commission enjoys widespread support among Guatemalans. As if to underscore the effectiveness of the panel, which works alongside Guatemala’s attorney general to build corruption cases, the commission announced arrests in two corruption cases last week, including one involving a former mayor of Quetzaltenango, one of the country’s largest cities.

The government’s campaign against Velasquez — to the extent of defying the court — has set off alarms.

“If they resist obeying the court, then we are talking about a technical coup,” said Karin Slowing, an independent analyst and columnist for the newspaper Prensa Libre. “We are talking about a rupture that can take us in any direction.”

If congress, which is largely hostile to the commission, supports the government’s defiance of the court, “the country’s institutions will break,” Slowing said.

The last time a president openly defied the constitutional court was in the 1990s, and the conflict was only resolved when the army stepped in on behalf of the judiciary to enforce its decree.

It is unclear what will happen this time. Morales is supported by a powerful cadre of former military officers, but the United States’ support for the commission, which was unqualified last year, has waned in recent months.

At the same time, public pressure has been a deciding factor on this issue within Guatemala. In 2015, hundreds of thousands of protesters took to the streets to decry corruption, and the president at the time, Otto Pérez Molina, was forced to step down and face charges brought by Velásquez.

Morales appears determined to avoid his predecessor’s fate, and he has shown a willingness to push the nation to the brink to do so.

Last week, protests against Morales swelled in the countryside, but were more modest in the capital, where the government deployed police officers and soldiers to control the crowds.

Slowing said that one reason for the more muted response in the capital was because the private sector, which ultimately supported the protests in 2015, has largely backed the government against the commission this time.

This article originally appeared in The New York Times.

Azam Ahmed and Elisabeth Malkin © 2018 The New York Times