ONLY A FEW months ago, the Andean nation of Bolivia seemed to be on its way to healing, after a year that had thrown its political future into jeopardy. Luis Arce, a candidate of the country’s socialist party, had won the Oct. 18 presidential elections. His opponents — Carlos Mesa, who ran against him on a centrist platform, and the conservative then-interim president, Jeanine Áñez — had accepted the result. And Mr. Arce had pledged to govern on the basis of unity and conciliation. Thus did Bolivia appear to exit a crisis that the leader of Mr. Arce’s party, former president Evo Morales, precipitated by attempting to steal a fourth term through election fraud in 2019, leading to often-violent demonstrations, the military’s abandonment of the Morales-led government — and Mr. Morales’s departure to exile.

Now, unfortunately, Mr. Arce appears to have reverted to a more one-sided and vengeful leadership style characteristic of Mr. Morales, who has returned to Bolivia and still wields considerable power. On March 13, the government jailed Ms. Áñez and two former members of her cabinet, threatening them with prosecution and long prison terms; warrants are out for several other former top officials. These actions follow an amnesty for Mr. Morales’s supporters accused of human rights violations while Ms. Áñez was in power, as well as the institution of de facto political loyalty tests for key government employees.

Mr. Arce’s government claims that it is merely enforcing laws against sedition that Ms. Áñez purportedly broke by fomenting a “coup” against Mr. Morales. Ms. Áñez is certainly not blameless in Bolivia’s problems, having governed high-handedly, including by trying, shortly after she took office, to shield security forces from punishment for sometimes deadly violence against pro-Morales protesters.

Yet Ms. Áñez, facing pressure from human rights advocates, withdrew that decree; and the accusation at the core of her arrest now — that she plotted with the Bolivian military and others to overthrow Mr. Morales — is at odds with historical reality. Mr. Morales lost power because of his own attempt to subvert the 2019 election — which Organization of American States (OAS) observers confirmed at the time — and the Bolivian people’s massive rejection of it in the streets. Ms. Áñez succeeded to the presidency under a tenuous but constitutionally prescribed emergency process; and, to her credit, she peacefully ceded power to Mr. Arce when he won last year.

Tens of thousands of Bolivians have taken to the streets in opposition to what Mr. Arce is now doing. Bolivia’s Catholic bishops have issued a statement against what they called an attempt to turn the justice system into a partisan weapon and to “create a false account of history, inventing the truth and manipulating the conscience of Bolivians.” The OAS secretariat also decried the arrest of Ms. Áñez, prompting Mr. Arce’s minister of justice to threaten OAS Secretary General Luis Almagro with prosecution.

The Bolivian government’s lawless course threatens further chaos, if not civil war and outright dictatorship, at a time when the country, among the hardest hit by covid-19 in the world, should be fighting the pandemic. The Biden administration should lead a regional effort to preserve democratic stability in this long-suffering country, lest crisis turn into catastrophe.

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