Of all the difficult jobs on Parliament Hill these days, few are about to become as demanding as that of Quebec adviser to Prime Minister Stephen Harper.
That is so because one of the hardest calls Harper will have to make soon is how much of his political future he can afford to stake on Quebec Premier Jean Charest.

The nature of that call will determine how quickly the Prime Minister moves on his core plan to rebalance the federation. His assessment of the Quebec political outlook could also determine the timing of the next federal election.
Only two months ago, Harper's victory seemed to herald a new era of Quebec-Ottawa co-operation. Having played a key role in making Harper Prime Minister, Quebec clearly offered the best prospects for a Conservative majority in the next federal election.

Between now and then, a solid Harper/Charest partnership seemed like an obvious win-win for both leaders. But what looked like a no-brainer on election night now could turn into a major headache for the Conservative government.

Over the past two months, Charest's domestic situation has deteriorated. His standing in the polls has plunged to new lows.

A planned spring relaunch has turned into a public-relations quagmire.
A cabinet shuffle designed to bring new blood into the government has left pools of bad blood on the floor of the provincial Liberal caucus.

An inaugural speech designed to turn a new page has turned out to be so bloated with disconnected intentions that it went down like a lead balloon.
And now a local controversy over the future of a park has degenerated into a symbolic battle that is pitting the premier against some of the most iconic lobbies in Quebec.

None of this has anything to do with Harper or with the sovereignist/federalist debate - indeed, the perceived weakness of the current sovereignist leadership is Charest's last, best hope for re-election these days - but it does present the Prime Minister with two equally unpalatable notions.

The first is that Charest may be beyond his help; the second is that the Quebec premier has the potential to take him down with him.

If Charest were to be defeated between now and the next federal election, there would not be a shortage of voices who would interpret the result as a failure of Harper's Quebec agenda.

With the Parti Québécois back in power, Harper's bid to decentralize the federation would come across as a dangerous new way to empower sovereignists, at least in the rest of Canada.

With his strongest provincial ally out of play, the Prime Minister would face a distinctly more hostile group of premiers.

Not only would the PQ be back at the table, but Harper would also have to contend with the Ontario feathers he is currently ruffling as he pursues a strong alliance with Charest.

With the PQ back in power, there would, once again, be a referendum on the horizon - a prospect that has tended to strengthen Liberal support federally in the past.

Up to a point, Harper's options are devilishly limited.
He does not have an alternative federalist horse to back in Quebec.
Over the past few years, Mario Dumont's ADQ has been reduced to a regional force.

Besides, the Prime Minister cannot walk away from his own election commitments to Quebecers without squandering his hopes for significant gains in the province in the next federal vote.

His choice is not whether to dance with Charest but whether to do so to the slow beat of a waltz rather than that of a twist.

On paper, Charest has until the first half of 2008 to send Quebec to the polls.
But if he has not done so by next spring, it will be because he has failed to rekindle his fortunes. By then, time could be running out for the premier.
Under that scenario, Harper might find it safer to precede Charest to the polls than to risk becoming the first federal casualty of the fallout of a defeat of Quebec's federalist government.