In the 2000 municipal elections, the UDM won control of the
King Sabata Dalindyebo Local Municipality. The party lost the council during the
floor crossing period, however, and this would begin a time of decline; In the
2004 general election, nine members were elected to the National Assembly, five fewer than were elected in the 1999 election. The UDM lost its position as the official opposition in the Eastern Cape after two of its members in the Eastern Cape Legislature had defected to the splinter
United Independent Front in 2005. On October 8, 2008, the UDM announced its kickoff of the
2009 general election campaign. It also welcomed over 300 former members of the ANC who had left their former party following the deposition of former president
Thabo Mbeki in September 2008. Almost 1,000 former
African National Congress members joined the party after the ANC recalled President Mbeki and replaced him with
Kgalema Motlanthe. Nevertheless, the election would continue the downward trend of the UDM, with the party retaining only four MPs with 0.8% of the vote and losing its representation in all provinces except the Eastern Cape, where it was pushed into fourth place. In 2014, a faction of the
Congress of the People led by
Mbhazima Shilowa joined the UDM. This helped to strengthen the party in its Eastern Cape stronghold, where it likely gained support from many previous COPE supporters. In the
2014 general elections, UDM support remained at very low levels in eight of the provinces, and it failed to re-establish itself nationally, but made a convincing rebound in the Eastern Cape, where it overtook COPE to become the third-largest party. The increase was especially convincing in the King Sabata Dalindyebo region. However, this new growth had largely evaporated by the time of the 2016 local elections. The
general election of 2019 saw its support drop further. The UDM lost half of its seats both nationally and in the Eastern Cape, becoming the seventh-most supported party nationally, and fourth-most in the Eastern Cape. In the
2021 South African municipal elections, party support declined even further, leaving the UDM as the twelfth-most supported party nationally. == Election results ==