The speaker of the lower house of Brazil's Congress said on Thursday that manipulating government accounts, the main opposition case for ousting President Dilma Rousseff, was not sufficient grounds to impeach her, according to Reuters. Speaker Eduardo Cunha's comments were a blow for Rousseff's opponents since he is the man in Congress who decides whether to begin impeachment proceedings or shelve requests. "The fact that accounts were manipulated does not necessarily mean that the president committed a crime. They are two different things," Cunha told reporters. Cunha, a declared enemy of Rousseff who has changed his tone since damaging corruption accusations emerged to threaten his political survival, said an impeachment process would have to prove the president broke the law by violating budget laws. Opposition leaders filed a new petition to Congress on Wednesday seeking to unseat her for allegedly doctoring government accounts in 2014 and into her second term. The request is considered the most serious attempt so far to impeach Rousseff because it is based on a federal audit court ruling that her government manipulated its accounts to disguise the size of the deficit and allow for more spending in the run-up to her narrow re-election last year. The petition reinforced an earlier one by adding accusations that Rousseff signed spending decrees for 820 million reais ($210 million) without seeking the approval of Congress, an impeachable violation of budget laws if proven. Cunha appears to be taking his time to decide on the new request. The speaker said he would take a copy home with him to read over the weekend. "We can't rush to a conclusion. We must be very careful about this," he said. If he takes up the request, months-long impeachment proceedings would begin, prolonging a political crisis that has deepened Brazil's worst economic slump in 25 years. Rousseff's opponents need a two-thirds majority in the lower house to trigger an impeachment trial in the Senate. Rousseff aides are confident they can block that vote with the support of Cunha's fractious PMDB party, Brazil's largest. Cunha is under pressure to resign after Swiss prosecutors informed Brazilian authorities that he had millions of dollars in secret bank accounts in Switzerland that they suspect came from bribes in the Petrobras corruption scandal. The speaker can escape ethic committee hearings with the help of Rousseff's Workers' Party, which could explain why he is in no hurry to set the impeachment ball rolling.