Although “poison pill” probably deserves to be added to the “overused political words” list, here’s the latest on a possible poison pill:

The Conservative government plans to bring in legislation connected to the harmonized sales tax in the coming months, giving it the tool to bring about its own demise should Prime Minister Stephen Harper wish to capitalize on the Liberals’ current misfortunes.

Government officials confirmed that the agreements under which Ontario and British Columbia will harmonize their retail sales tax with the federal goods and services tax call on Ottawa to bring forward HST legislation by March 31, 2010.

It seems obvious the Bloc would vote against this. The NDP would have a hard time supporting this but, you never know, maybe Jack will meet an unemployed single mother in Sudbury who pleads with him to vote for it, prompting a change of heart. Because, gosh darn it, he’s thinking about the people!

But, failling that, the fate of the HST legislation would lay squarely in the hands of the Liberals.

Which would be, to put it bluntly, rather awkward. Having already split the party in Quebec, going to the wall against the HST would risk alienating many provincial Liberals in Ontario and British Columbia.

Which explains the rather…I guess the polite word would be “nuanced” position, that Michael Ignatieff has taken on the HST. In short: he’s against it, it’s a bad idea, but he’ll honour the deal between Flaherty and the provinces.

So, given that, how do you vote against a piece of legislation you’ve promised to honour? Then again, how do you vote confidence in a government you’ve explicitly said you don’t have confidence in? Presumably the Liberals will need to find an answer to one of those questions, unless Flaherty rolls the HST up into his next budget.

It’s also a dicey situation for the Tories who probably don’t love the idea of framing the election around their support for what is widely perceived to be a tax increase. After all, that makes it a lot harder for them to go on about Michael Ignatieff’s secret plan to raise taxes.

So…yeah…fun times ahead!