Among these three Russian parties only — United Russia (ER), New People (NL), and the Liberal Democratic Party of Russia (LDPR) — which one will achieve the largest increase in the number of seats it holds in the State Duma of the Federal Assembly of the Russian Federation, comparing the results of the next Russian parliamentary election (scheduled for September 2026) to the current (pre-election) seat composition?

rationale:

The Baseline Advantage The decisive factor in this market is the current (pre-election) seat composition, as the question resolves on the largest increase in seats, not the largest total. Official Duma sources and consensus reporting indicate the baseline is United Russia (ER) 310, the Liberal Democratic Party of Russia (LDPR) 22, and New People (NL) 15 2 sources. ER's baseline of 310 is notably depressed by 14 vacancies compared to its 2021 election result of 324 ru.wikipedia.org. This artificially lowered baseline provides ER with a structural "gift," drastically lowering the bar for the ruling party to record a significant seat gain. Note that some older sources list stale 2021 figures (e.g., ER 325, LDPR 23, NL 10) dumatv.ru; if these fallback figures were used, ER's path to a win would be much narrower, but the 310/22/15 baseline is highly likely to govern.

United Russia's Electoral Dominance ER remains the clear favorite due to its heavy structural advantages and absolute dominance in the 225 single-member districts (SMDs) 2 sources. While the Kremlin has reportedly lowered ER's list-vote target from 55% to around 45–50% amid economic and war-fatigue pressures 3 sources, ER still polls well ahead of the pack at 34–37% en.wikipedia.org. Pro-Kremlin expert projections anticipate ER securing 51–54% of the list vote and 190–205 SMDs 2 sources. Under these central projections, ER would finish with roughly 315–340 total seats, translating to a substantial gain of +5 to +30 seats from its 310 baseline, making it the most probable winner.

The Path for New People (NL) New People is the strongest alternative because it starts from a much smaller baseline of 15 seats and has demonstrated the clearest growth trajectory of any systemic party since 2021 2 sources. NL currently polls at 8–10% en.wikipedia.org and is projected to win roughly 20–30 list seats and up to 5 SMDs 2 sources. This translates to a plausible gain of +5 to +18 seats. The primary risk to an ER victory is a scenario where ER hits the lower end of its reduced electoral KPIs, netting little to no gain, while NL comfortably adds 10 to 15 seats to its small baseline.

LDPR's Arithmetic Challenge and Tie-Breakers LDPR is a distant third because its arithmetic for achieving the largest gain is uniquely challenging. Although it generally outpolls NL slightly (10–13%) and has a superior SMD presence 3 sources, it must overcome a higher baseline of 22 seats duma.gov.ru. To beat NL in this metric, LDPR would have to finish roughly 7 seats ahead of it, requiring a significant overperformance that current polling does not support. Finally, tie-breaking rules offer a slight buffer for ER and LDPR: if two parties record the exact same seat gain, the tie is broken by total valid votes polymarket.com. This heavily favors ER over both rivals, and gives LDPR the edge in a pure LDPR–NL tie.