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.

Anyone who thinks it's smart to cut immigration is sentencing Australia to poverty.

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

I do not believe we can effectively move Australia to a lower emission economy, which is what we need to do if we're going to make a contribution to a global reduction in greenhouse gases, without putting a price on carbon.

The royal commissions are successful and effective when they have a focused terms of reference and can do the job quickly and report. And then action can be taken.

Broadcasters or politicians or writers who think that they are respecting Struggle Street, the battlers, by dumbing things down into one-line sound bites are not respecting them, they are treating them with contempt. It's our job above all in politics to tackle the big issues and to explain them.

Americans understand that they have no stronger ally, no better friend, than Australia.