Premier Doug Ford should not be using Ontario taxpayers’ money to fund his government’s advertising campaign against Prime Minister Justin Trudeau’s federal carbon tax.

When they were in opposition, the Progressive Conservatives said they wouldn’t do this.

They also promised to scrap the law passed by former Liberal premier Kathleen Wynne that opened the floodgates to partisan advertising in Ontario years ago.

Ontario Auditor General Bonnie Lysyk has criticized the new PC ad, which emphasizes the costs of the federal carbon tax by showing nickels spewing out of gas pumps, furnace vents and supermarket shelves, without mentioning its rebate system.

Lysyk said this ad would not have passed muster under the non-partisan advertising law approved by the Dalton McGuinty Liberals, which Wynne scrapped, over Lysyk’s objections.

Lysyk is being consistent. She’s making the same argument against partisan PC ads as she used to make against partisan Liberal ones.

By contrast, it’s not a valid argument for the Ford PCs to say the Ontario Liberals used to do the same thing.

Nor is it a valid argument that Prime Minister Justin Trudeau’s Liberals have launched a pro-carbon tax campaign, using taxpayers’ dollars, and that interim federal auditor general Sylvain Ricard recently reported there are insufficient controls on partisan federal Liberal advertising.

Governments that defend their bad policies by arguing other governments of a different political stripe are as bad or worse, are using a strategy known as “whataboutism.”

It’s not a valid defence. It’s an excuse.

Ford and the PCs promised they would be better than the Liberals on this issue.

They should live up to it.