An earlier version of this editorial incorrectly stated that former Peruvian president Alejandro Toledo had been charged with accepting bribes in exchange for government contracts. A judge has ordered his preventive detention, but Mr. Toledo has not been formally charged.

THE CORRUPTION scandal that has disrupted governance in Brazil for nearly four years has been slowly spreading across Latin America, thanks to the confessions of a construction company that paid hundreds of millions of dollars in bribes in more than a dozen countries. The vice president of Ecuador was sentenced to six years in prison last week for accepting payoffs from the Odebrecht construction company, and Venezuelan President Nicolás Maduro has been accused by a company official of taking campaign contributions in exchange for contracts.

Nowhere has the damage been greater, however, than in Peru, where two former presidents have been charged with crimes — and a third may be removed from office this week. What makes the trouble worse is that President Pedro Pablo Kuczynski, the target of an opposition-led impeachment vote scheduled for Thursday, has not been shown to be guilty of any wrongdoing, other than misleading the public.

There's little question that Peru's fragile democracy was penetrated and corrupted by Odebrecht, which admitted in a 2016 settlement with the U.S. Justice Department to paying $29 million in bribes in the Andean country. But the company says it did not make illegal payments to Mr. Kuczynski, a former Wall Street banker who took office just 16 months ago on an anti-corruption platform. Instead, it paid some $4.8 million to two consulting companies owned by Mr. Kuczynski or a close associate over the course of a decade.

Mr. Kuczynski, who was serving in a previous government during some of the contracts, says he had recused himself and did not know about the work. He says he was involved in only one transaction, for consulting on an irrigation project, while he was out of office. There is no evidence that he accepted bribes or campaign cash in exchange for government contracts, the allegation made against former presidents Alejandro Toledo and Ollanta Humala. But Mr. Kuczynski made misleading statements, denying until last week that he had any connection to Odebrecht.

That has been seized upon by the populist leader he defeated in the 2016 election, Keiko Fujimori, who is herself under investigation for receiving Odebrecht money. Last week Ms. Fujimori launched an impeachment motion against Mr. Kuczynski on grounds of "permanent moral incapacity," a charge that requires no tangible demonstration of wrongdoing, much less a trial. With 71 seats in the 130-member parliament, Ms. Fujimori easily gathered the votes necessary to mandate a vote on removing Mr. Kuczynski, who controls only 18 parliamentary seats.

Mr. Kuczynski has handled the Odebrecht affair poorly, but his removal would do only more damage to Peruvian democracy. Having been fairly elected, he would be ousted at the initiative of his defeated opponent on vague grounds after a week-long process. The constitution says his term should be completed by one of his two vice presidents. But Ms. Fujimori, who has already orchestrated the removal of three cabinet ministers and is targeting several supreme court justices, appears intent on dismantling the government piece by piece. That is not corruption fighting; it is abuse of power.