After a period of relative quiet, a flurry of polls towards the end of May suggests that levels of support for parties have stabilised over the last month after some clear shifts since the start of the year.
According to the most recent calculations of the pooled polls model, Law and Justice (PiS) remains clearly in the lead on 38%, which is roughly the same amount of support it obtained in the 2015 elections. Civic Platform lags behind on 26%. All other parties have less than 10% support, with the Democratic Left Alliance (SLD) and the Kukiz'15 social movement on 9%, while the Polish Peasant Party (PSL) and the Modern party (Nowoczesna) are on 5%.
Looking at trends since the start of the year, there are several noteworthy developments. During March, support for PiS fell by a significant amount, but the party has arrested that decline since the beginning of April. During the same period, support for PO has steadily risen, although the rate of growth has slowed in the last couple of months. Several recent polls put PO on nearly 30%, although this is partly offset by the regular monthly CBOS polls, in which PO always does significantly worse than in other polls.
After stabilising its position in March, Nowoczesna has slipped again since the start of April, in several cases polling well below the 5% threshold. There is no certainty that the party would return to parliament if an election were held tomorrow. On the other hand SLD, which at the start of the year was not polling significantly above the threshold, has established a stable base of support sufficient to gain it seats in parliament. Support for Kukiz'15 and PSL has remained largely stable since January.
On current polling, PiS would not have a single-party majority and would have to rely on Kukiz'15, which would make for a numerically comfortable but ideologically volatile coalition, or on PSL, which would make for an ideologically more stable but numerically wafer-thin majority. It should be kept in mind that it is by no means certain that PSL and Nowoczesna would make it into parliament: if both were to drop definitively below the threshold, PiS would probably gain the seats it needs for a single-party majority (perhaps with a few defections from Kukiz'15), while PO would be the biggest beneficiary from the absence of Nowoczesna.