The embattled chairman of the Republican Party of Florida was censured and stripped of his duties and salary on Sunday, decisions that all but ousted him from the party’s top post as he faces a criminal investigation into an accusation that he sexually assaulted a woman.

In an emergency meeting in Orlando, the party’s executive committee stopped short of immediately forcing out Christian Ziegler, the chairman. But the votes to declare him unfit for office, remove almost all of his authority and reduce his salary to $1 were seen among many party members as the final steps before his potential removal from office.

Mr. Ziegler, 40, has been under criminal investigation in Sarasota, Fla., where he lives, since October, when a woman told the police that he had sexually assaulted her. He has not been charged and has denied any wrongdoing. He has also refused to resign since the investigation became public last month, despite sustained pressure from Republicans, ranging from the governor to county-level chairs, for him to step down.

Republicans have said that they consider the criminal investigation against Mr. Ziegler serious, and a distraction that would make it untenable for him to raise funds and rally the party going into an important presidential election year.