In 1898-1900 it merged with SDL (Social Democracy of Lithuania) to become SDKPiL (Social Democracy of the Kingdom of Poland and Lithuania), and its fortunes revived a little.
Luksemburg and the SDKPiL opposed Polish independence on several grounds.
The SDKPiL failed to take into account the strength of the Polish will to re-create a state, and consistently underestimated the element of Russian nationalism contained within Bolshevik revolutionary aspirations.
To complicate things further, the bulk of the SDKPiL membership were seen as marginal to Polish national identity.
In 1918 SDKPiL and PPS-Lewica (PPS-Left) amalgamated to form the KPRP (Communist Worker's Party of Poland).