Palermo, May 23 - Arguments about punishment for mafia collusion are divisive and unnecessary, the Speaker of the Senate said Thursday. Pietro Grasso spoke during ceremonies to mark the 21st anniversary of the assassination of anti-Mafia prosecutor Giovanni Falcone near Palermo. "The only possible division in the fight against corruption is the one between the honest and corrupt," said Grasso. The issue hit the headlines this week when a Senator allied with ex-premier Silvio Berlusconi's People of Freedom (PdL) party briefly tabled a bill that would drastically reduce the penalties for mafia collusion. Amid an immediate outcry, the bill was withdrawn. "It was such an unpresentable bill that it was withdrawn immediately," said Grasso earlier in the day. "Shame brought that bill down. I hope they don't repropose it". Falcone was killed along with his wife and three bodyguards on May 23, 1992, when a bomb exploded on the Trapani-Palermo highway near Capaci in Sicily. Two months later, his friend and anti-Mafia partner Paolo Borsellino was killed by the Mafia in a car bomb attack in Palermo, which left five of his bodyguards dead and 20 people injured. Grasso added that it was important that citizens see their politicians working together for justice, in order to maintain confidence in government institutions. "The State must be and appear to be strong, serious and credible".