It's a brave politician who dares take on Rupert Murdoch, especially in an election year. But that's exactly what Malcolm Turnbull looks set to do.

Mark Twain once advised to "never pick a fight with people who buy ink by the barrel" and - with control of around 70 per cent of the country's big-city newspapers - Murdoch certainly buys in bulk. Just as importantly, his papers have never been afraid to go to war with their enemies.

Former communications minister Stephen Conroy discovered this when he tried to regulate the print media. The Daily Telegraph ran a front page comparing him to Stalin, Mao and Fidel Castro (Hitler, curiously, didn't get a guernsey).

Three years after Conroy's failed push, media reform is back on the national agenda.