The prime minister doesn't need to give voice to his exasperation with the Senate expense scandal as he heads to Calgary for a two-day policy convention.

Stephen Harper pantomimes his frustration almost every time he rises in the Commons to answer another barbed question.

He raises his palms heavenward, shakes his head balefully and repeats how "crystal clear" he's been since May in telling Senator Mike Duffy that he had to repay $90,000 in improperly claimed living expenses, in saying his former chief of staff resigned for deciding, on his own, to pay that money back out of his own pocket, and in reiterating that — had he known — he would have directed Nigel Wright not to do it in the first place.

Written down like that, it does all seem crystal clear. Except the prime minister has said more than that. Much, much more. And what he's said about Wright, in particular, keeps changing. From month to month, week to week, day to day.

Here's what Harper said May 19 in accepting Wright's resignation for his role in the Duffy affair:

"I accept that Nigel believed he was acting in the public interest, but I understand the decision he has taken to resign. I want to thank Nigel for his tremendous contribution to our government over the past two and a half years."

Compare that with what the prime minister said in a radio interview on Monday:

"As you know, I had a chief of staff who made an inappropriate payment to Mr. Duffy. He was dismissed."

Or to what Harper told the Commons on Tuesday.

"Once again, Mr. Speaker, on our side, there is one person responsible for this deception, and that person is Mr. Wright. Mr Wright by his own admission. For that reason, Mr. Wright no longer works for us."

Changing message

Fired or resigned. Acted in the public interest, or out of deception. These are just two examples of Harper's changing answers. And that makes the prime minister a key player in keeping the Senate scandal alive heading into a policy convention that was supposed to lift the party away from the Senate morass and into the orbit of priorities they can campaign on in 2015.

Still, turning on your former chief of staff seems out of sync for a leader who demands absolute loyalty from his people, and a strict adherence to message control.

When Wright first resigned, a number of his former colleagues praised his integrity, work ethic and honesty. They called his decision to personally repay Duffy's expenses a regrettable error.

Those same people are silent now as Harper dismantles Wright's reputation.

Oxford defines to deceive as to "deliberately cause (someone) to believe that something is not true, especially for personal gain."

There's been no suggestion Wright was motivated by personal gain. In fact, just the opposite is true. He dashed off a payment in an attempt make a political problem go away for the prime minister.

Prime Minister Stephen Harper speaks with Senator Claude Carignan, the Leader of the Government in the Senate, following a party caucus on Parliament Hill on Oct. 30. (Adrian Wyld/Canadian Press)

Harper's new lines suggest he's trying to put more distance between himself and the actions of his former chief of staff. He is doing so using the bully pulpit of his office and the privilege attached to anything said in the Commons.

In the meantime, the facts in the Duffy-Wright affair are not yet fully known. The RCMP continue to investigate.

In reality, Harper and the Conservatives want to deflect attention from him, and to keep it on the Senate where the debate over whether to suspend Duffy, Pamela Wallin and Patrick Brazeau without pay drags on and on.

Their punishment was to have been meted out before this weekend's convention. It was supposed to allow Harper to tell party faithful that these three senators had been held accountable for misusing taxpayers' money.

Instead, Harper spent the week fending off questions about his own role, and his changing answers.

At the crossroads

The Senate isn't on the official agenda in Calgary, but Conservatives acknowledge the expenses controversy and Wright-Duffy affair will play out in the hallways among party supporters who were promised Senate reform by Harper, not scandal.

It's also the focus of a daylong panel discussion leading into the convention, sponsored by former Reform Party leader Preston Manning's foundation, which says the movement to change the Senate is at a crossroads.

"It's time to assess where we've been, where we are and where we are headed," the foundation says in promoting the event.

How the prime minister deals with the Senate question is another matter.

Harper will address the convention Friday night. Certainly some of his advisers are suggesting he steer clear of the subject altogether. Senior cabinet ministers are already signalling the focus of the speech will be on the Conservatives most familiar calling card.

"I think Canadians expect us to focus on the issues that matter to them and their lives," Treasury Board President Tony Clement said Wednesday after the Conservatives' weekly caucus meeting. "And we are doing so. The biggest trade agreement in the history of our country. Focusing on jobs. That's what people care about."

Only the media, he suggested, cares about the Wright-Duffy affair, or whether the prime minister's former right-hand man betrayed him.

Pressed for an answer, Clement stuck to what is now the approved message.

"The prime minister has been clear on that."