Hours after senators voted overwhelmingly to put her on trial for alleged financial trickery, President Dilma Rousseff of Brazil denounced the effort to impeach her as a coup.

“I may have committed errors, but I never committed crimes,” Ms. Rousseff said.

That is debatable, but Ms. Rousseff is right to question the motives and moral authority of the politicians who are seeking to oust her. The Brazilian president, who was re-elected in 2014 for a four-year term, has been a lousy politician and an underwhelming leader. But there is no evidence that she abused her power for personal gain, while many of the politicians orchestrating her ouster have been implicated in a huge kickback scheme and other scandals.

Brazil’s Supreme Court ruled last week that Eduardo Cunha, the veteran lawmaker who has led the effort to oust Ms. Rousseff, must leave office to stand trial on corruption charges. Vice President Michel Temer, who took charge of the country on Thursday, could be ineligible to run for office for eight years because election authorities recently disciplined him for violating campaign finance limits.