OTTAWA - Michael Ignatieff faces the latest test of his leadership mettle Monday when he'll announce the Liberal party response to the current Conservative economic report card.

Putting Stephen Harper's minority government on "probation" -- subject to periodic status reports -- was a workable stalling tactic when the freshly installed Liberal leader wanted to avoid defeating the Tory budget back in January.

But with the second of three Liberal-demanded reports on the economic stimulus package now in the books, the pressure increases on Ignatieff to make a coherent case why the Harper government should either live on, or fall.

It is not an enviable choice for the Liberal leader: Precipitate a possible summer election few Canadians want and that his party is not prepared to fight; or give the green light to a slick Tory stimulus update that one parliamentarian likened to a ShamWow infomercial.

Liberal MP Ralph Goodale told CTV's Question Period on Sunday that his party will assess the truthfulness and effectiveness of the Tory economic plan. But that's not all.

"Third, and most importantly, is what is in the best interests of Canadians," said Goodale. "What do Canadians want? It's a very serious decision."

Ignatieff begins the week with a news conference Monday morning in Ottawa to announce his intentions, and ends it Friday when the Liberals have an opportunity to bring a voteable non-confidence motion against the government -- the last before the House rises for the three-month summer recess.

On his way into a fundraiser for Liberal MP Gerard Kennedy at Toronto's Old Mill Inn on Sunday, Ignatieff remained silent when asked questions about the pending decision.

Liberal insiders maintain Ignatieff is deeply and genuinely conflicted over the call.

He's certainly not getting any help from his fellow opposition leaders.

NDP Leader Jack Layton and Gilles Duceppe of the Bloc Quebecois have been goading Ignatieff with reminders of humiliating Liberal capitulations by his predecessor Stephane Dion.

Any combination of 18 Bloc, New Democrat and Liberal MPs absent for a non-confidence vote would ensure the Tory minority survives. But the Liberals can't bank on finessing a moral victory combined with a welcome strategic defeat.

Bloc MPs, citing the need to be in Ottawa to vote, refused to pair with government ministers who wanted to attend an airshow in France this week. That forced Defence Minister Peter MacKay, among others, to cancel their trip.

The NDP also appears prepared to have all hands on deck.

"Political parties have to make the decisions based on what they believe in," said party director Brad Lavigne. "We have a belief that this budget is bad."

Conventional wisdom in Ottawa -- based primarily on polling trends -- is that the Bloc and NDP would both lose seats if an election was held now, and therefore won't help the Liberals defeat the government.

If they do, the Tories have already started their talking points.

Conservative MPs Pierre Poilievre and John Baird both used their Sunday appearances on CTV to reprise the unloved coalition theme, alluding to the formal pre-Christmas entente between the Liberals and NDP, backed by the Bloc.

Ignatieff has made it clear the coalition concept is dead, but that won't stop the Tories from attempting to resuscitate it in order to rattle voters.

"What we don't want to see is more political games," Baird opined.

"We want to see a focus on the economy. We at the federal level, we have put politics aside."

Rest assured, no one in Ottawa is putting politics aside.

Consider that the current non-confidence tempest centres on a Liberal-inspired economic report card pegged to an arbitrary date that the Tories used to launch an all-out partisan communications exercise.

As Chris Charlton, the NDP MP from Hamilton, Ont., put it Friday, Harper's invitation-only, mock town hall meeting in Cambridge, Ont. -- hosted by unctuous TV-host-turned-Tory Senator Mike Duffy -- "had all the substance of a 30-second spot for ShamWows."

Improbably, that just might be enough to trigger Canada's second federal election in nine months.