The Free Trade Hall in Manchester was once the only public building in the world named after an idea. It was built on St Peter's Field, where in 1819 the entry of the cavalry began a bloodbath in the act of quelling a rebellion.

After a tumultuous week in the markets, with dissent in the air, Labour Cabinet ministers are staying in the hotel that now stands on that very site. Their task this week is deceptively simple: they will avoid a bloodbath only if they articulate a clear direction.

The need to do so is the more pressing because the money has run out. Labour ministers often say that they are in virgin territory in their eleventh year in government, and so they are. But the greater challenge is how to govern well now that the party's over.

The boom has bust. The usual dividing line - investment versus cuts - is incredible now that the money has been spent. The party finances are heading the way of Lehman Brothers. A sort of low-volume panic is audible. The ghosts of defeat were haunting the TUC. The polls in marginal seats suggest that the coalition built in 1997 is breaking apart in spectacular fashion.

Against this inauspicious backdrop there is, it has to be said, a deep crisis of leadership. The Prime Minister is fond of saying that troubling times are a test. They are, but not quite in the sense that he means. Gordon Brown's position is fortified by talking up the scale of the current crisis. The fortunes of his Government will be impaired by the same act.

This is an echo of the Government's defining error - the tendency for policy to be suborned to political tactics. Mr Brown is in a hole, digging. This week is about whether he can stop.

The early signs are not encouraging. The announcement of nursery places for two-year-olds is the same sort of expensive central initiative that has worked only too rarely. The completion date of 2018 also fails the most basic political test of all - it makes you laugh. If a new initiative is delivered daily with the newspaper headlines, this will be politics as usual.

In fact, the Government is in deeper trouble than it needs to be. The blend of free markets, social justice and internationalism is still a potent mix. And when the historians strip out the politics to judge the policy, this year has items in the credit column. Nuclear power has been given the go-ahead; a decision has been reached on Crossrail; the reform of incapacity benefit was bold.

But, even on this generous reading, the Government somehow seems very much less than the sum of its parts: hence the need for someone to step up this week and define the Government's future in a compelling way. Bromides from the podium about the long-term challenges and the importance of renewal will not be enough. If that is all they have to say, it may be salutary that Cabinet ministers have been allotted only seven minutes to speak. They should remember, though: the Gettysburg Address took less than half that time.

There are plenty of false friends prepared to supply the elusive definition. Most of the critics of the Prime Minister actually offer something worse - all the tumult of unseating him in the service of a political position that is a plea for a bigger defeat. The politics of the fringe could be explosive. But the bulk of the nostrums there will point, unbeknown to their authors, to the fringe of politics.

The stage is set for someone to articulate Labour's vision of lives not lived at the mercy of others. Disraeli once called Manchester the philosophical capital of the world. That might be asking for too much. But he who is willing to be the philosopher may yet be the king.