Liberal MP Julie Bishop backs the IMF push for a top marginal tax rate of 30 per cent. Actually, given the way these things work, it’s more likely to be an ambit claim from within the ‘official family’ (Treasury, Treasurer’s Office and RBA) than a suggestion originating from the IMF itself. Ken Parish has already put up a substantial critique, as well as proposing more work for me in the form of an estimate of the revenue cost (I’ll do it soon, I promise!).

There’s only one thing left to bug me. In my interview with Terry Lane on the National Interest, I said that the incentive case for lower tax rates was nonsense and that a stronger argument was that based on the claim that high tax rates promoted tax avoidance. Sure enough, this was the point Julie Bishop ran with. I don’t know if she was listening but, if so, she obviously missed my observation that New Zealand had tried a 30 per cent top marginal rate, found it did no good, and abandoned it.