The Vice Chair, alternatively referred to as the Vice Chairman, Vice Chancellor, Vice chair of the Senate, or even the Senate Speaker, held the responsibility of presiding as an officer within the Galactic Senate of the Galactic Republic. Their primary function was to uphold established procedures and protocol within the chamber, and to maintain order among the senators in their capacity as speaker.
During the Republic's final years, Mas Amedda occupied the position of vice chair, serving under both Supreme Chancellor Finis Valorum and his successor, Sheev Palpatine of Naboo. Following the conclusion of the Clone Wars, Amedda transitioned to the role of Grand Vizier within the newly established Galactic Empire.
This bureaucratic role, known as the Vice Chair, Vice Chancellor, or Senate Speaker, was connected to both the Galactic Senate and the Office of the Chancellor, representing the legislative and executive branches of the Galactic Republic, respectively. As the Senate's speaker, the vice chair's duty was to ensure order among the senators from across the galaxy. In the waning years of the Republic, Vice Chair Mas Amedda meticulously enforced protocol and procedures within the Senate. While the Chagrian politician believed he was maintaining governmental functionality, in reality, bureaucrats like Amedda often caused delays that rendered the Senate ineffective.
During Lina Soh's time as Chancellor, Larep Reza held the position of Vice Chancellor. Reza, who attended the unfortunate Republic Fair, was considered to be Soh's likely successor at the end of her term.
In 32 BBY, Queen Padmé Amidala appealed to the Galactic Senate for assistance for her home planet of Naboo, which had been invaded and occupied by the Trade Federation Droid Army. When representatives from the Trade Federation and Malastare demanded that the Senate establish a committee to examine the validity of the young monarch's claims, Vice Chair Mas Amedda advised Supreme Chancellor Finis Valorum to yield to their demands. Amidala, unwilling to leave the Naboo under Federation control while the Senate debated, called for Valorum's removal, hoping that his replacement would be more decisive.
Despite Valorum's removal, Amedda remained in his position as vice chair under the new chancellor, Sheev Palpatine, previously the senator representing Naboo. He continued to serve in the chancellery throughout the Republic's remaining years, which were marked by the Separatist Crisis and the subsequent Clone Wars. The vice chair was also among the select few aware of Palpatine's identity as a Sith Lord, actively assisting the chancellor's schemes by manipulating the Senate to grant him increased wartime powers.
Shortly after the fall of the Jedi, Vice Chair Amedda stood beside Palpatine as the newly self-proclaimed Galactic Emperor announced the establishment of the First Galactic Empire. Amedda remained a key figure in the Emperor's inner circle, serving as one of Palpatine's closest aides and advisors under the new title of Grand Vizier.
The "Chancellors, Senators and States Persons of the Republic" encyclopedia contains an error, presenting the Vice Chair and Vice Chancellor positions as distinct roles.