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The 2007 parliamentary election marked a significant defeat for the Kaczyński brothers, Lech and Jarosław, who had dominated Polish politics for several years. Lech Kaczyński, then serving as president, saw his Law and Justice party (PiS) lose power to the more centrist Civic Platform (PO) led by Donald Tusk. This loss marked a major setback for the Kaczyński brothers' conservative agenda and their influence on Polish politics.