Northern League party leader Umberto Bossi leaves the party's headquarters in Milan, Italy, Thursday, April 5, 2012. The firebrand founder of a populist, Italian anti-immigrant party, whose crucial support kept Silvio Berlusconi in power in three governments, resigned Thursday amid a widening corruption scandal over party funds. Umberto Bossi tendered his resignation as Northern League secretary, the top post, at a summit of party officials in Milan and repeatedly rebuffed pleas by his colleagues to change his mind, said a League statement.