The economic crisis, the fall of the Berlusconi’s cabinet in November 2011 and the formation of the technocratic cabinet led by Mario Monti provided the ground for the general elections held in February 2013, which reached a stalemate, contrary to what most observers expected. The center-left coalition won in the Chamber but not in the Senate. The result in the Senate made it impossible to form a majority coalition between Bersani’s left and Monti’s center, which many considered the most likely outcome of these elections. In the end, the only available option for the PD, the winner in the Chamber, was to form a cabinet with Berlusconi’s PdL. There are many factors explaining this destabilizing result. The first and most important is the success of a brand new anti-establishment party, the Five Star Movement, which attracted voters from across the political spectrum and became the largest party in the country. The second is the inability of the center-left not only to extend its electoral base at a time when the center-right lost almost half of the votes received in 2008, but also to keep its previous electorate. The third factor is the peculiar nature and functioning of the electoral system for the Senate.