CLOUDS IN THE CRYSTAL BALLS

Not even historians now pay much attention to the National Liberals, the group that joined a Conservative-dominated coalition in 1931 and lingered on until 1968, though during the post-war period with only a name to distinguish them from the Tories.

That is one fate that could meet the Liberal Democrats after concluding the coalition, but the deal made was probably inevitable given the outcome of the election.

In a strange way, the country got what it voted for - it wanted Labour out, did not fully believe the Tories had changed from the bad old days and sought a Tory-lite government.

However much Lib Dems might wish that the parliamentary arithmetic was otherwise, it isn't, and it can't be. The proposed deal with Labour was barely tenable, and not at all after Labour started to fall apart over the idea.

Given Labour's record, its claim to be a progressive party is surreal and that record is the reason why Labour is now less a natural ally for the Lib Dems than it may have been in the past. What liberal after all, if forced to choose, wouldn't rather have Ken Clarke than Jack Straw as justice secretary?

There is a serious argument to be made that the Lib Dems should have let a Tory minority government take office and not embroiled themselves in government. But it is hard to see how the Lib Dems could then have avoided taking the blame for whatever the Tories did while gaining none of the potential advantages of the coalition. It is even harder to see how the party could have survived a quick second general election.

The coalition agreement contains things that will both please and infuriate Liberal Democrats, which is inevitable in such a negotiation. Of the concessions the Lib Dems made, only one is instantly contentious, which is early public spending cuts. Having spent the campaign arguing about the dangers of cutting too far and too fast, the party is now complicit in doing just that.

When the promised further and deeper cuts really bite, the party will find itself in a novel role, for which it must be ready. For the past several decades, its main complaint has been being ignored by the public. The Lib Dems are instead likely to become robustly hated, in particular in those parts of the country that depend heavily on public sector jobs.

That could open up fissures in the party as Labour seeks to recapture these areas. More widely, all governments become unpopular, so what will happen to those who want to vote against the coalition in Tory areas where Labour now hardly exists? If the Lib Dems cannot continue to attract this vote by arguing that their presence stops worse excesses, a vacuum will open for the full chamber of horrors of UKIP, the BNP and local populists of various kinds.

It may be that the coalition delivers political benefits to the Lib Dems but, since it is now easier to see the pitfalls, it would be as well for the party to plan for these.

The party must not only remain independent and make its own policy, but also its leaders must encourage this. Sooner or later, it will need a platform on which to fight another election. Saying, “We're a bit like the Tories but not quite as much,” will not do.

Essential too will be tolerance within the party. A lot of people don't like the coalition and will blame it for local losses. If coalition supporters try to drive their opponents out, neither side will have a party before long.

It will also be essential to be clear what the party is for. It exists to advance liberalism, not to tone down someone else's philosophy. It hopes one day, aided by reformed voting perhaps, to lead a government, but it will not be able to do either of these things if it has been ruined by in-fighting, become an appendage of the Tories, or both.

Only a fool would make firm predictions now about the outcome of the next general election, but the many pitfalls and opportunities are obvious.

The pessimistic scenario would see the Lib Dem ministers slowly morph into the coalition's representatives within the Lib Dems, rather than the reverse, with the party detached from and resentful of the government, split, ineffective, and facing a massacre, alterative vote or not.

The optimistic scenario is that the referendum on AV is won, the pain of spending cuts is gone through long before any election, the public is impressed by the Lib Dems in government and uses its newly-powerful votes to keep them there. Local parties discover that defending the party's national record is not so hard and Labour departs for a bout of internecine warfare over why, post-Blair, it exists.

The 1930s coalition was almost wholly Tory. The wartime government was all-party. There are no precedents for what we have now. From Nick Clegg to the local Focus editor, quite literally no-one knows what they are doing.