Immigration has been a vexed subject in Australia and used in political campaigns, past - and present.   We are a nation, after all, that enacted what became known as the White Australia policy way back in 1901. And who can forget John Howard’s potent ‘stop the boats’ election campaign? Meanwhile, just recently, we’ve experienced an unprecedented surge in migrant numbers. So the issue is once again at the heart of a federal election, to be held in less than five weeks’ time.  Today, senior economics correspondent Shane Wright on what impact immigration has on our economy.  For more: Read Shane Wright's piece in The Age and Sydney Morning Herald here.Subscribe to The Age & SMH: https://subscribe.smh.com.au/See omnystudio.com/listener for privacy information.