OTTAWA — Federal Liberals know they've been trapped by the Harper Conservatives on the HST but they're in no rush to decide which paw to stick into the snare.

Liberal Leader Michael Ignatieff said Friday he'll take his "own sweet time" deciding whether to support or oppose legislation the government plans to introduce next week, enabling Ontario and British Columbia to harmonize their provincial sales taxes with the federal GST.

He said no decision will be taken until he's had a chance to consult with his caucus next week.

The Bloc Quebecois took some of the pressure off the Liberals, announcing Friday that it will probably support the legislation. The Bloc's support would be enough to ensure the bill will pass.

Still, Liberal MP Bob Rae frankly admitted the Grit caucus is torn over what to do, aware there's a good chance they'll be politically mangled no matter what they decide.

"I'm not waffling, I'm skating," Rae said in a burst of candour rarely seen on Parliament Hill as he dodged questions about how Liberals will vote on the legislation.

"Let me be absolutely clear," he added with a grin. "We'll have a position when the vote comes and we've got some reflecting to do, that's all."

If Liberals support the legislation, they risk the wrath of voters in Ontario and B.C. who are increasingly angry at the prospect of paying more for many goods and services. They also risk abandoning the anti-HST vote to the NDP, which has been nipping at Liberal heels in some recent opinion polls.

NDP Leader Jack Layton wasted no time Friday taunting the Liberals and urging them to "join our campaign" to stop the HST.

"The tax is coming at the wrong time and hitting the wrong people and it should be stopped," he said in an interview.

Layton went so far as to draw a parallel with the anti-taxation protest that spawned the American revolution, saying any move to expedite the HST legislation without parliamentary hearings would be akin to "the kind of thing they had a tea party about in Boston."

On the other hand, should Liberals oppose the legislation, they risk infuriating the Liberal governments in both provinces. Federal Grits desperately need help from their provincial cousins, particularly in vote-rich Ontario, if they're to have any hope of winning the next election.

Ontario Premier Dalton McGuinty argued Friday that the HST will create 600,000 jobs over 10 years and is vital for Ontario's future prosperity. He urged all federal politicians to set aside partisan interests and support it.

"From time to time, we are called upon to do things in (the name) of leadership which are not necessarily easy but in our heart of hearts we know are the right kinds of things to do," McGuinty said.

"That's what the HST is all about."

B.C. Finance Minister Colin Hansen suggested that no matter what federal politicians may think of the HST, they have no right to second-guess the decisions taken by provincial government to proceed with it.

Beyond stirring up provincial animosity, federal Liberals would risk appearing opportunistic and unprincipled were they to turn their backs on a harmonization policy they vigorously promoted and defended when they were in power.

Indeed, they even initially lauded the Harper government's deal to ease the way for Ontario and B.C. -- with $4.3 billion and $1.6 billion in respective transition funding -- until public opinion turned sour.

Rae acknowledged the potentially lose-lose nature of the decision facing Liberals.

"You've described very well the tensions," he admitted. "You know we have a lot of things to consider as we make a decision."

While Liberals wrestled with what to do, the Harper government eased up the pressure somewhat.

After circulating an internal memo Thursday that amounted to throwing down an ultimatum to Ignatieff, the Tories issued another directive Friday insisting they're not trying to "embarrass, box in or gain an advantage over the federal Liberals" by pushing ahead with the HST legislation next week.

"Our goal is to secure official Opposition support for the provincial-choice framework, not to score cheap points."

The Tories, who want the issue well out of the way before a possible federal election next year, said the vote on the HST legislation won't be a matter of confidence over which the minority government could fall. Nevertheless, they said a vote to defeat the legislation would be final.

In Toronto, Finance Minister Jim Flaherty framed the legislation as simply providing the technical support to enable the provinces to reform their tax systems as they see fit. He urged MPs to respect the tax choices made by provincial governments -- a tactic echoed by some Liberal insiders.

But Rae and Layton ridiculed the Tories' attempt disavow any responsibility for the HST.

"They can't pretend it isn't their baby. I mean it's not immaculate conception here," said Rae.

Layton said he doubted B.C. and Ontario would have proceeded with harmonization if the federal government hadn't lured them with the promise of transition funds.