In the 1991–1992 transition to multiparty elections, UPADS was part of the
National Alliance for Democracy (AND), which also included the
Congolese Labour Party (PCT). In the
parliamentary election held in June–July 1992, UPADS won 39 out of the 125 seats and, together with its AND allies (mainly the PCT), gained a slight majority of 64 seats in the
National Assembly. A UPADS-led government, with
Stéphane Maurice Bongho-Nouarra as prime minister, was appointed after Lissouba took office, but the PCT withdrew from the pro-Lissouba alliance and joined the opposition after it received only three positions in the government, causing the alliance to lose its parliamentary majority. The
Union for Democratic Renewal (URD) opposition coalition and the PCT were therefore successful in defeating Bongho-Nouarra's government in a no-confidence vote on 31 October 1992. Lissouba consequently dissolved the National Assembly and called a new election; in which the Presidential Tendency won only three of the 11 available seats. to June 2001 as Minister of Construction.
Joseph Kignoumbi Kia Mboungou was the UPADS presidential candidate in the
presidential election held on 10 March 2002; he took second place but received only 2.76% of the vote, with Sassou Nguesso winning by an overwhelming margin according to official results. The party's first extraordinary congress was held on 27–28 December 2006, with 954 delegates. On this occasion
Pascal Tsaty-Mabiala was elected as the Secretary-General of the party, succeeding . Also elected at the congress were a 601-member National Council, a 135-member Political Bureau, and 25 Vice-Presidents; the Vice-Presidents included major figures in the party such as
Joseph Kignoumbi Kia Mboungou,
Alphonse Poaty-Souchlaty,
Ange Edouard Poungui,
Clément Mouamba,
Jean Itadi, and
Mireille Lissouba. The party put forward about 50 candidates. The party received three seats out the 46 declared in the first round. Tsaty-Mabiala said that the party would only participate in the second round of the election in July if the electoral rolls were improved, voter registration cards were properly distributed, and the composition of the electoral commissions was changed. He also said that the second round should be delayed to allow time for these things to be done. The election was delayed by two weeks. In results announced after the second round, the party had a total of 10 seats in the National Assembly. Tsaty-Mabiala denounced the results as fraudulent on 11 August and said that the election was neither transparent nor fair. He alleged that five UPADS candidates, in Mossendjo, Moutamba, Nkayi, Mabombo and Dolisie electoral districts, had won but were deprived of victory in the results. The party appealed to the Constitutional Court. Ibovi subsequently announced a correction in the results for one of the electoral districts UPADS claimed to have won, Mabombo (in
Bouenza Region), which had gone to Marcel Kalla in the previous results, but which Ibovi said was actually won by the UPADS candidate, Christophe Moukouéké. This raised the number of UPADS seats to 11. In early October 2007, Tsaty-Mabiala said that UPADS would not participate in any national unity government because there had not been an agreement on resolving the country's problems. At a meeting on 24–25 August 2008, the UPADS Political Bureau expelled nine executive members from the party; these included Christophe Moukouéké and
Victor Tamba-Tamba, both founding members of UPADS. This decision was said to have been taken in order to restore harmony and discipline within the party. Along with the
Union for Democracy and the Republic (UDR-Mwinda) and the
Rally for Democracy and Development (RDD), UPADS formed the
Alliance for the New Republic opposition coalition on 11 May 2007. Complaining that the 2007 parliamentary election and the
2008 local elections were "masquerades", this coalition withdrew from participation in national and local electoral commissions in August 2008. It wanted a new and independent electoral commission, in addition to an "all-inclusive national dialogue" prior to the
2009 presidential election. Former Prime Minister Ange Edouard Poungui was chosen as the UPADS candidate for the 2009 presidential election by the UPADS National Council in a primary election on 30 November 2008. His sole rival for the nomination, Joseph Kignoumbi Kia Mboungou, withdrew from the vote, complaining of "lack of transparency in the process", and Poungui, as the only candidate, received about 85% of the vote. However its candidacy was later rejected by the Constitutional Court on the ground that he had failed to establish his continuous residency in Congo-Brazzaville for at least two years. In the three following parliamentary elections, always under the leadership of Pascal Tsaty Mabiala, UPADS never managed to weaken PCT's absolute majority, remaining the main opposition force (tied with UDH-Yuki in
2017 and
2022) but always obtaining between 7 and 8 seats. Tsaty Mabiala was also the party's presidential candidate for the
2016 presidential election, finishing fourth with 4.67% of the votes, while the party did not contest the following presidential election in
2021. ==Electoral history==