In Impeaching Ex-Premier, Junta Revives Thailand’s Divisions

BANGKOK — After months of claiming to be an honest broker in this deeply divided country, Thailand’s military junta swung decisively to the side of the conservative Bangkok establishment on Friday, imposing a five-year ban from politics on a former prime minister who is detested by the elites but loved in the provinces.

The junta also announced that Yingluck Shinawatra, the former prime minister of the government that the military overthrew in May, would be indicted on a charge of criminal negligence, which could lead to 10 years in prison.

The decision to aggressively pursue Ms. Yingluck risks prolonging what has already been a lost decade of street protests, two military coups and ample bloodshed on the streets of Bangkok. It also revives a power struggle that has reduced Thai economic growth to near zero.

Bitter recriminations and cynicism about the military’s intentions that had been muted since the coup resurfaced quickly Friday after the junta’s legislative assembly voted 190 to 18 to impeach Ms. Yingluck. The impeachment carries a five-year ban from politics.

The impeachment process was more show trial than legal proceeding: All the members of the assembly were handpicked by the junta, and the military never explained how someone who is no longer in power could be impeached.

Both the impeachment and the criminal charges against Ms. Yingluck have been spearheaded by Vicha Mahakhun, a member of the National Anti-Corruption Commission and a longtime foe of Ms. Yingluck’s movement.

During the impeachment hearings, Mr. Vicha responded to the charge that there was no concrete evidence of Ms. Yingluck’s involvement in corruption, telling the former premier: “Your behavior signifies a strong suspicion of corruption.”

The prime minister, Mr. Vicha said, had refused to heed his warnings about the cost of the rice subsidy. “This has led to enormous damage to the country,” he said. “This has given rise to continual violence in the country.”

Mr. Vicha is notorious among supporters of Ms. Yingluck for helping rewrite the Thai Constitution after the 2006 coup, saying at the time that elections were “evil.”

In the end, the impeachment proceedings came to resemble what the military had vowed to avoid: a proxy battle between the elected politicians overthrown in the coup and the military that overthrew them.

The New York Times