Senate president Renan Calheiros said in a special session that he would ignore an order by Speaker Waldir Maranhao to send the whole procedure back to square one. Rousseff faces being suspended from office in the vote starting Wednesday.

“I ignore” the order, Calheiros said, sparking raucous applause and angry shouting from rival senators on the Senate floor.

Calheiros called Maranhao’s intervention in the impeachment drama “absolutely untimely” and “playing with democracy.”

Maranhao made a surprise announcement earlier declaring null and void an April vote by the lower house to launch the impeachment proceedings and send Rousseff for trial in the Senate.

The legislator said he was accepting an appeal from Rousseff’s solicitor general that the original vote had been conducted in an illegitimate way. He called for a fresh vote in the lower house in the coming days.

That would drag the process back from the Senate and restart the whole chain of events.

The Senate is scheduled to vote on Wednesday on opening the trial against the president, who faces being immediately suspended for six months.

It was not immediately clear whether the Supreme Court would have to intervene in the clash between the upper and lower houses.