Answer
Mirek Topolánek resigned as leader of the Civic Democratic Party (ODS) in 2010, after losing the 2010 Czech legislative election. He had been the leader of the party since 2002, and had led the party to victory in the 2006 legislative election. However, the party lost the 2010 election to the Social Democratic Party (ČSSD), and Topolánek resigned as leader.