With the Gillard government being consistently outgunned and just plain monstered in public debate, it has more cause than ever to regret the departure of former finance minister Lindsay Tanner, who was one of the few politicians with the ability and inclination to actually explain things to the electorate. His talents were on display again last night when he delivered the annual Walter Lippmann lecture in Melbourne. (No, not that Walter Lippmann -- this one.)

Tanner's theme was the economic benefits of immigration -- not the narrow "arithmetic" sort, but the advantages that flow from greater ethnic and cultural diversity. Multiculturalism, as he put it, is not a matter of "moral vanity or middle-class indulgence", but an economic necessity.