"Under international law an illegal war amounts to the crime of aggression and in some countries around the world a crime of aggression is one in which they exercise jurisdiction. So the possibility really can't be excluded that if messrs Blair and Howard at some point in the future travel after they've left office to a country which, for example, has an extradition agreement with another country where you have an independent prosecutor."
Precedents do exist. Chile's dictator and US and British friend Augusto Pinochet always thought he would live above the law, but he will be hopefully hounded for the remainder of his life to answer charges of human rights abuses during his reign of terror. Likewise, Israel's Ariel Sharon. He has never faced a court to answer for his role in the 1982 massacres in Sabra and Shatilla. The Belgium courts were considering pressing charges against Sharon but relented after US pressure. In early 2005, US Defense Secretary Donald Rumsfeld was in the sights of the German courts for his role in torture in Iraq. And let's not forget Henry Kissinger, friend of the rich and powerful (including NSW Premier Bob Carr). To this day, he refuses to travel to certain countries due to potential prosecution, due to his role in subverting democracies from Chile to Cambodia.
It is the height of Western imperial arrogance to suggest that only "they" - African despots, Iraqi dictators or Cambodian generals - should be held accountable for past crimes and not "us", the benign leaders of so-called open democracies.
A victim of Pinochet's reign of terror, tacitly supported by the US government, Joyce Horman, perfectly articulates the need for Western accountability:
"The American military and the American government have an incredible amount of power and the abuse of that power was typified by the Chilean coup. For Americans to be bumping off Americans in foreign lands is not what American citizens want their government to be doing."
Howard, Blair and Bush have been warned.