When Stephen Harper kicked off the election campaign on the August long weekend he said voters would have a clear choice between proven leadership they can trust, or unproven risky alternatives.

Three weeks in and trust has indeed become a central theme, just not in the way Harper intended.

The Conservative leader wants the question of trust framed around which of the federal party leaders is best equipped to manage the Canadian economy, which of them is the one voters can trust to keep taxes low and their families safe.

But the past week of testimony at the Mike Duffy trial by Harper's former chief of staff Nigel Wright is helping the other party leaders reframe the question.

They say it's really about whether voters can trust the Conservatives to tell the truth about their efforts to hush up the Mike Duffy affair before it became public.

The official line from Harper is that Wright and Duffy are the only two at fault, and therefore the only two who need to be held to account.

However, the information coming out of the trial is that most of Harper's senior advisers were also in on the scheme, including Ray Novak — the man who replaced Wright as chief-of-staff.

A longtime Harper confidante, Novak was chosen for the role because he was said to be in no way tied to Duffy, or the feverish scheming in 2013 to get the beleaguered senator to repay the $90,000 in expenses that Wright concedes he may actually have been entitled to claim.

A police statement given by Harper's legal adviser, Benjamin Perrin, puts Novak in the room during a conference call on March 22, 2013, when Wright told Duffy's lawyer that he, Wright, would be the one repaying the money, a decision Wright confirmed in an email to Perrin and Novak the next day.

Names with no faces

Now these are just names to most Canadians. Names with no faces. People who hold titles with no particular significance outside Ottawa.

But together they formed a close-knit group around Harper, the people he relied on and trusted to carry out his wishes, to give him advice on the most serious political issues of the day. It's a role Novak continues to hold.

Ray Novak Stephen Harper

Ray Novak, the prime minister's current chief of staff. When did he know Nigel Wright had paid for Mike Duffy's Senate expenses? (Adrian Wyld/Canadian Press)

Senior Conservatives insist they knew all this was coming out of Wright's testimony, and they had their answers ready.

Novak, they said, didn't read that fateful email. Novak, said Wright, was in and out of the room during the conference call.

Even so, the daily barrage of questions at Harper's campaign-stop sessions with the media — sessions he might have avoided by not calling the election so early — have clearly put him on the defensive, forcing him to repeat set answers about Wright and Duffy when the questions are about Novak and Perrin.

"I am not going to cherry-pick facts that are in dispute," Harper said Wednesday in London, Ont. "The fact of the matter is I have held those who are responsible accountable."

Novak himself isn't speaking. The man who has spent virtually his entire working career with Harper is unavailable. His continued presence on the campaign is limited to work behind the scenes, out of eyeshot and earshot though not out of mind.

Someone needs to be fired: NDP

None of this is helping Harper as he seeks that fourth consecutive mandate, a victory that eluded every prime minister since Wilfrid Laurier more than a century ago.

The Liberals say Harper is protecting Novak, and refusing to take responsibility for his actions and to tell the truth to Canadians.

"It goes to the heart of the trust that Canadians have, not just in this prime minister, but in the office of the prime minister regardless of partisanship or who we vote for," Liberal leader Justin Trudeau said Wednesday during a campaign stop in Winnipeg.

"All Canadians need to know the prime minister and his office behave with integrity."

NDP leader Tom Mulcair says someone needs to be fired.

"And that's the person who named Mike Duffy to the Senate. It's the same person who hired that chief of staff, the person who is in charge of the Prime Minister's Office. That's the prime minister."

CANADA-ELECTION/

Mike Duffy's lawyer on Thursday suggested to Nigel Wright that the suspended Senator was forced to tell the public he repaid his expenses. (Chris Wattie/Reuters)

The New Democrats are happy to campaign against Harper's record on the economy. And they are.

But NDP strategists say that campaigning against Harper's record of scandal is far more effective at the moment in communicating the message that it's time for change.

Liberals say they're also picking up that desire for change, and trying to channel these revelations arising from Wright's testimony into their own messaging.

Both parties continue with their plans to roll out policy, with the bulk of the platform to be released after Labour Day when Canadians are more likely to be engaged.

Meanwhile, the Duffy trial pounds on, with Perrin and another senior Harper staffer, Chris Woodcock, scheduled to testify before the trial takes a break later this month until after the Oct. 19 election.

It's too early to say just what impact this testimony in August will have on voter intentions in October.

Polls suggest there is an unusually large number of uncommitted voters in this unusually long campaign, voters who are swinging back and forth between the major parties.

They may well have to trust their own instincts when the time comes to make a decision.