That same year, the group renamed itself once more to the Socialist Party. It contested the general election of the following year under that name, running five candidates in Dublin. Higgins ran again in Dublin West, and though his personal vote share had dropped to 16.2%, he won a seat on the sixth count. He would be the party's only successful candidate, though candidates in Dublin North and Dublin South West also polled well, at 7.2% and 4.8% respectively. In 1998, the party ran in the Northern Ireland Assembly election, though their sole candidate in Mid Ulster fared poorly, receiving just 0.2%.
2002 saw a slight expansion in the party's activity, with the party's first candidate outside of Dublin being Mick Barry of Cork North Central. He received just 2.1%, but the four candidates in Dublin fared well. Higgins was re-elected with an increased 21.5%, continuing his trend of coming second in the poll. Clare Daly's vote also rose in Dublin North to 12.5%, though she failed to win a seat. In the next year's Northern Ireland Assembly election, two Socialist candidates ran in Belfast, though again their performance was lacklustre compared to the party in the Republic.
The early to mid 2000s saw the Celtic Tiger reach its peak - as a result, by the next general election in 2007 most voters were satisfied with the government while those who voted against it voted for Fine Gael and Labour. The Socialist Party experienced a disappointing election, with Higgins losing its sole seat in the Dáil. Both he and Daly experienced significant decreases in their votes, while on the other hand the Dublin South West and Cork North Central candidates each experienced slight increases in support. The party had lost its foothold in the Dáil, and needed a fortunate result in the next general election.
That election occurred in 2011, with the economy in a recession and a hugely unpopular incumbent government. In the months before this election, the Socialist Party had joined with the People Before Profit Alliance and the Tipperary-based Workers and Unemployed Action Group to form the United Left Alliance. This electoral alliance provided an advantage for both of the Dublin parties. The Socialists' strongest results were in the north and west of the county, while the PBPA performed well in the south east. Running under the same banner, the two parties secured two seats each: the PBPA in Dublin South Central and Dún Laoghaire, and the Socialist Party winning in Dublin West (with Joe Higgins regaining his seat) and North (Clare Daly coming third in the poll). Mick Barry won an impressive 9.2% in Cork North Central, though he still came short of winning a seat. New candidates in Limerick City, Laois-Offaly and Carlow-Kilkenny each polled between 1 and 2% - disappointing results, but nonetheless represented a slow expansion in the electoral activities of the Socialist Party, which may continue throughout the next general elections as the Irish political culture continues to change.
See: The United Left Alliance parties' first preference votes, 2011