Senator RUSTON (South Australia) (15:00): Mr President, I ask a further supplementary question. Given the Prime Minister's promise immediately before the last election— Senator Birmingham interjecting— Senator Conroy: Senator Birmingham, couldn't you get a question up today? Honourable senators interjecting— The PRESIDENT: Order! Order, on my right and my left. Senator Ruston is entitled to be heard in silence—on both sides. Senator RUSTON: Given the Prime Minister's promise immediately before the last election that there would be no carbon tax under the government that she led—which was broken in spectacular style—coupled with the government's existing plans to extend the carbon tax to the Australian trucking industry, why should Australian farmers or families believe any assurances Labor gives that it will not extend the carbon tax beyond that in the future?