In economics, one of the most important concepts is 'opportunity cost' - the idea that once you spend your money on something, you can't spend it again on something else.

While our energy efficiency is improving, there is a very high correlation, almost near perfect correlation, between GDP growth, and energy usage.

On balance, after weighing the arguments, I believe that the time has come for Australia to create a new sovereign wealth fund.

I'm sick of the cover-ups, I'm sick of the lies, and so are the bloody veterans, that come out daily of the department's mouth.

It's really corny to say, but if you are happily married and have good kids, that is about 98 per cent of what you should be seeking to achieve.

You will never find a better friend to the United States than Australia.

I am an ambitious person, but I am not ambitious in the sense that I want jobs only for the sake of them... I am here to do things I think are worthwhile. I am always careful that the political positions I take are consistent with good policy. I would not want to be prime minister of Australia at any price.