In the final weeks of the 2006 federal election, Stephen Harper’s Conservatives were between five and 10 points ahead of Paul Martin’s Liberals in the polls.

An increasingly desperate Liberal party launched a series of attack ads targeting Harper’s supposed “hidden agenda,” the most notorious of which suggested that the then Conservative leader’s plan to bolster the number of soldiers available for disaster relief efforts in urban Canada were really earmarked for a more nefarious purpose.

“Stephen Harper actually announced he wants to increase the military presence in our cities. Canadian cities. Soldiers with guns. In our cities. In Canada. We are not making this up,” the ad said, over the sound of a beating war drum.

The ad was so alarmist it was quickly pulled — and parodied.

“In 1963, In Dallas, Democratic president John F. Kennedy was shot and killed. Where was four-year-old Stephen Harper? We don’t know. He’s not saying. We didn’t make this up,” teased the National Post.

It was the perfect example of the political golden rule posited by academic and former Harper campaign manager Tom Flanagan that attack ads are less effective when the target is more trusted than the source of the attack.

Plus ça change, plus c’est la même chose.

The Liberal party is even further behind in the polls now and has once more resorted to the “hidden agenda” chestnut.

It is a short speech in the House by a Liberal MP that does not include the familiar old tune. Karina Gould, the government House leader, has been at the forefront of saying that Pierre Poilievre does not want to reveal to Canadians what he would do if elected.

The suggestion in recent days has been that Poilievre would axe the jobs of tens of thousands of public servants, kill the Liberal-NDP dental plan, end pharmacare coverage, defund the national child-care program and make it harder for a woman to have an abortion.

A more dispassionate look at what a Poilievre government would do in power suggests it might well do some of those things. He has promised to balance the budget, lower taxes and increase military spending. The math on that doesn’t work unless he finds savings elsewhere.

But polling is clear that chopping social programs indiscriminately would not be popular.

The most recent Abacus Data poll shows that making housing more affordable, balancing the budget, cutting personal income tax, eliminating the carbon tax, dealing with climate change and reducing the current level of immigration have majority support.

But cutting public funding to English-language CBC, ending child-care, shutting down the dental-care program and taking action on abortion do not.

The Abacus poll suggests nearly 50 per cent of respondents believe a Conservative government will eliminate the dental program, and 45 per cent think it will take action on child care.

A poll by the Angus Reid Institute earlier last month said the prospect of a Conservative government made nearly half of Canadians feel afraid, and a narrow majority said they bought into the “hidden agenda” imputation.

Conservatives may chortle at its past failure, but it remains a vulnerability that can’t be ignored.

Former Harper adviser Ken Boessenkool told me in a recent video interview that in 2006 the Conservatives countered the charge by releasing a detailed platform with new policy announcements every day. “We never made it explicit but the implicit argument was, ‘they have to do all this stuff they talked about, so they’re not going to have time for their hidden agenda, and we like their public agenda,’” he said. “That really worked for us in our polling… and the concern went away.”

In advance of releasing an election platform, Poilievre could allay the worst fears that are being stoked by the Liberals, just as he did last year when he said he would honour the increases in health transfers negotiated with the provinces. He has also said there will be no changes on abortion, same-sex marriage or cannabis laws if he becomes prime minister.

He might want to extend that guarantee to the nascent dental program.

The program is the kind of European-style health-care hybrid of public and private provision that could be a model for other areas of the system. It appears to have overcome its early, ahem, teething problems, and is providing coverage for people who were previously reluctant to go to the dentist. It would seem to be an extremely good addition to the list of “programs to keep.”

On the other hand, pharmacare, which is a provincial jurisdiction, is a more likely candidate for the chopping block. As is the national child-care program, which has repeated Quebec’s mistakes when it comes to lack of availability for low-cost spaces.

There will be changes under the Conservatives, which is what the polls suggest the vast majority of Canadians want, even if it is just in the form of a new messenger.

But Poilievre could calm anxieties by making it clear that programs that are working will be safe in his common-sense revolution.

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