As CBC's Evan Solomon reported this weekend, the New Democratic Party may soon be on the hook for the thousands of dollars in House money that it spent on satellite office staff and mailouts that have been retroactively deemed an improper use of parliamentary resources.

For the NDP, however, the lasting cost of the expense controversy in which the party has found itself may be the damage that it will do to the party's perennial efforts to style itself as the Jiminy Cricket of the Commons.

One of the few perks of having never sat on the other side of the House, after all, is being able to sit back and look smugly superior while the other two parties are frantically lobbing charges of past and present political perfidy across the aisle, interrupting the mutual destruction pact only to inject the occasional chorus of "Liberal, Tory, same old story."

No matter how many times their rivals have dredged up that unfortunate misunderstanding over the rules governing the sale of ad space at party conventions — which is, at least federally, the closest until now that the NDP had ever come to a scandal involving taxpayer money — they've never managed to make it stick.

(Not like how sponsorship haunts the Liberals, or Mike Duffy's expense claims cling to the Conservatives, anyway.)

But funnelling thousands of dollars in taxpayer dollars to staff out-of-town caucus outreach offices and thinly veiled get-out-the-byelection vote mailings?

Now that's something an opposition researcher can work with.

Not only is it easy to outline in a sound bite of 140 characters or less, but it plays directly into the persistent collective suspicion that virtually every elected official and political party truly believes themselves to be, to paraphrase the phrase made famous by former Liberal MP David Dingwall, "entitled to their entitlements."

It's easy to see why the Liberals — and, to a lesser extent, the Conservatives — have been so eager to circle the flaming torches around the New Democrat caucus.

NDP playing offence, not defence

What is far more difficult to fathom, however, is why the New Democrats have mounted such a high-risk defence.

From the moment the story hit the headlines, they've been on the offensive: decrying the other parties for conspiring against them from behind the curtain of the secretive all-party Board of Internal Economy, and dismissing the parallel investigation by a House committee as a kangaroo court.

Party leader Tom Mulcair came close to losing his temper during a post-caucus scrum, bickering with journalists over whether the rules on out-of-town staff had been "amended" or "changed," and accusing one journalist of having "made up" a question about an ongoing Elections Canada investigation into the mailings.

While appearing before committee, he mocked Conservative backbencher Stephen Woodworth for using the wrong Latin legal term, and suggested he pick up a copy of his book.

Meanwhile, NDP MPs attempted to stage a 'gotcha' rebuttal by putting forward documents they claimed showed that a Conservative MP's constituency office operating out of the same address as a party-owned workspace, but which was subsequently revealed to be two separate properties at the same mini-mall.

House of Commons Clerk Audrey O'Brien is expected to address the NDP assertion that House administration was fully aware of the expenditures when she returns from medical leave. (Adrian Wyld/Canadian Press)

When House of Commons Speaker Andrew Scheer later seemed to contradict the NDP version of events by telling the committee that neither he nor his office had been made aware of the expenses, the party issued a late-night press release that openly suggested his ability to do the job had been "compromised by the actions and intimidation of the Conservative government."

NDP House Leader Peter Julian has also filed a formal challenge to the Speaker questioning the legitimacy of the House order that established the committee investigation in the first place. If he dismisses the complaint, it will likely trigger another round of complaints over his independence.

The party may even be headed for a showdown with the unimpeachably impartial House Clerk Audrey O'Brien, currently on medical leave, who will eventually get the chance to respond to the NDP's claim that the bills for both the out-of-town salaries and the byelection eve mail drop were paid with the full knowledge and implicit approval of House administration.

If she contradicts Mulcair's claims, not only will the party's credibility be in the cross-hairs, but its leader will likely be accused of having deliberately misled the House.

Mulcair's office has also made it clear that even if called back by the committee for a second round of testimony, he has no intention of making a return appearance, which could set off a whole new debate over parliamentary privilege.

Payback may be just the beginning

Given the potential for such dire parliamentary consequences, one has to wonder how some New Democrats may be starting to think that would have been less painful for all concerned for the party to have backed down long before it got to this point.

After all, had they grudgingly admitted to what they could insist was an entirely unintentional error in interpreting the rules, cut a cheque to pay back every disputed cent and declared the matter closed, the story would have faded from the headlines weeks ago.

Instead, they may end up paying a much steeper price.