Are you in Australia right now ? There is a world of difference between what News Corp, Faifax, AFR etc papers have done in the past and what happened with the Daily Telegraph yesterday.
Why Murdoch wants Rudd to lose the coming federal election is not merely political, it is commercial. News Corp hates the government's National Broadband Network (NBN). The company has formed a view that it poses a threat to the business model of by far its most important asset in Australia, the Foxtel cable TV monopoly it jointly owns with Telstra.
Murdoch was a major force in getting Gough Whitlam (of the Australian Labor Party) elected which was probably his first major step into the political scene. He was also a major force behind the election of Malcolm Frazer (of the Australian Liberal Party) a few years later. Just because he elects leaders from the left or the right does not mean he isn't influencing them. Murdoch has long had a hand in picking the government of the day. Why he picks one leader or another is less of an issue than the fact he is picking leaders.
