Last night's drama in the UK parliament over the call for an EU referendum is over. Will it all blow over? For now, maybe, but the issue will come back. Wise politicians will be thinking ahead about what they should do when it does. For David Cameron, it looks like trouble.
The starting point is that there is mounting pressure for a referendum on the European Union in the UK. Why should this be? We operate a representative democracy, after all, and the issues are complex - not the sort of thing that referendums are supposed to be particularly good at sorting out. But there is a substantial body of public opinion who believe the country's membership of the Union is an outrage to our constitution. This has always been so - but while in the 1970s these were overwhelmingly older people, scepticism is now more widespread. The Tory Eurosceptics who entered Parliament last year are a younger breed, and to many a focus on Europe has reached obsessive proportions.
This scepticism has been fanned by the press. Why? Clearly newspaper proprietors don't like the EU for their own reasons - but surely it goes deeper than this. The EU is an easy target for our frustrations, in much the same way as ethnic or religious minorities used to be. They don't answer back. Exploiting this is one way to sell newspapers. Add to this the growing frustration with the Union right across Europe, and the steady fading of European idealism, and you have a ready explanation for rising scepticism.
It all looks very different, of course, once you are responsible for running the government. Here the thought of operating outside the EU, or even taking a detached stand within it, looks plain silly. And so you have a tension between the governing elite and a substantial body of public opinion. A referendum campaign seems to be one of the best ways of bringing this to a head. A campaign in the right circumstances has the support of many Europhiles too. They are sick of their steady retreat in face of the Eurosceptic onslaught, and long to turn and fight, even at seemingly hopeless odds - like the British soldiers retreating to the Marne in 1914.
So far so good. Now it gets complicated. Europhiles want a straight in-out referendum. This would force pragmatic sceptics, including large parts of the Tory hierarchy, into the "in" camp. To them, this is the basic question of principle anyway. Trying to have referendums on carefully negotiated treaty changes is a misuse of this method of democracy. Extreme Eurosceptics would be happy enough to go along with this, convinced as they are that the country would be much better off out, and that the public would rally to their cause.
But pragmatic Eurosceptics don't want this, for exactly the reason that the Europhiles want it. What they aim for is a changed relationship between the UK and the EU - and that a pre-emptive referendum on an in-out question would weaken their negotiating position. For them the main job of a referendum is to put a spanner in the works of the EU itself, by blocking any changes they dislike to the treaties. Pretty much everybody accepts that a UK referendum would have rejected any of the previous treaties (Maastricht or Lisbon in particular - though the former might have been quite close, in my view). The idea of a three way referendum, with a renegotiation option, in yesterday's motion was an attempt to win over these pragmatic sceptics. But it didn't really stand up to close examination - one of the bigger reasons why the motion fell so heavily.
But it is possible to see a the outlines of a deal coming out of this. First negotiate a new deal with the EU, then have an in/out referendum on its outcome. Sounds simple enough, but the renegotiation idea is fraught. Is it a new deal for Britain, or a more general rebalancing of Europe? I think the government has in mind the latter, drawing in allies from across northern and eastern Europe. The idea would be to use the Eurozone crisis as leverage. If the Union's constitution needs to be changed to make the Euro work, then this can be made conditional on other changes.
The trouble is that it is difficult to understand what the shape of this deal might look like. To the the EU core members (Germany, France, Italy and so on) the EU constitution is carefully balanced, with a free trade area on the one hand, and regulation to prevent a disorderly race to the bottom on the other. Besides a treaty change will have to go through referendums right across the Union - a nightmare as European politicians learn that a rejection of a treaty can earn them extra goodies.
And so the risk is that the government returns from the "renegotiation" without very much to show for it, and then be forced to hold a referendum on it. The prospects for a Britain-only renegotiation are even bleaker, as our bargaining position is so weak. This will place the pragmatic sceptics, like David Cameron and William Hague, in an impossible position. Yesterday's debate has reduced their room for manoeuvre, as the Economist's Bagehot column points out. They will have to produce something relatively soon.
One of Mr Cameron's main achievements has been to de-toxify the issue of Europe for the Tories. But the issue could yet return to destroy him, his government and his party. It will be the greatest test of his leadership.