The PPS was a part of the coalition government of Brazilian President Luis Inácio da Silva until December of 2004, when its national executive decided to withdraw its support. Ciro Gomes of the PPS did not resign his position as Minister for National Integration, leading to his being removed from the PPS's National Executive. At the 2006 legislative elections, the party won 21 seats in the chamber of deputies. At the same time, party members retained the state governorships of Mato Grosso and Rondônia.
The PPS suffered setbacks in the 2010 general elections. It won 12 seats in the Chamber of Deputies, no Senate seats and no state governorships.