Explaining Trumpery in terms of the attitudes of the Left alone gets the story precisely backwards. Yet that is what Peta Credlin, former chief of staff to prime minister Tony Abbott, now pundit about town, wrote on Sunday.

For the political class’ smug dismissal of voter concerns is a bipartisan sin. For Credlin to imply otherwise absolves herself, and her party, from their responsibility for engendering the anger to which she refers.

In a article that is by turns commentary on US Presidential candidates, gloss on the causes of Trump and attack on the Left, Ms Credlin does at least identify a subset...