With a marathon 17-hour debate continuing through the night ahead of a vote, the writing was already on the wall for Brazil's first female president.
Only a simple majority of the 81-member Senate is required to suspend Rousseff for six months pending judgement on charges that she broke budget-accounting laws. And shortly after 3:15 am in Brasilia (0615 GMT), the 41st senator declared his intention to back impeachment ahead of the vote.
A trial could take months, with a two-thirds majority vote eventually needed to force Rousseff, 68, from office altogether.
In the meantime, starting Thursday, Temer was to take over as interim president of Latin America's biggest country -- ending 13 years of rule by Rousseff's leftist Workers' Party.
Temer, from the center-right PMDB party, was preparing to announce a new government and says his priority is to address Brazil's worst recession in decades and end the paralysis gripping Congress during the battle over Rousseff.
A onetime Marxist guerrilla tortured under the country's military dictatorship in the 1970s, Rousseff has denounced the impeachment drive as a coup and vows to fight on during the trial.
Brazilian media reported she would be officially notified of the vote's result at 10:00 am (1300 GMT) Thursday and would make a statement to the nation. A crowd of supporters would gather outside to salute her as she drove off, a spokesman for her Workers' Party told AFP.