Serb nationalist Vojislav Seselj went on trial Wednesday on charges of inciting ethnic tensions that fueled Yugoslavia's bloody breakup, with prosecutors blaming him for atrocities carried out by Serb paramilitaries. Seselj - chairman of Serbia's main opposition party, the nationalist Serbian Radical Party - is one of the most senior political figures in custody at the Yugoslav war crimes tribunal. His trial marks one of the court's few remaining chances to hold Serbian leaders responsible for the atrocities unleashed by the dissolution of Yugoslavia in the early 1990s. A one-time close associate of late ex-leader Slobodan Milosevic, Seselj's extreme nationalist speeches spurred Serbs into murder, torture and rape as they pursued the goal of a "greater Serbia" by ethnically cleansing parts of Bosnia and Croatia, prosecutor Christine Dahl said. But, she said, he ultimately failed. "In the end, Mr. Seselj did not achieve a greater Serbia. He managed to achieve only a lesser Serbia and gave the world the phrase 'ethnic cleansing."'