The result in Eastleigh will have more impact on the immediate future of British politics than any by-election for decades.
The win for the Liberal Democrats will calm nerves in a party that would have gone into meltdown if it had lost. Nick Clegg can claim more credibly that when his party is strong locally it can still win. Although the result was calamitous for the Conservatives, coming third behind UKIP, the confidence boost for Clegg will lead to slightly more stability at the top of the Coalition. If Clegg had lost, the victim of another torrid election campaign in which he detected the malevolent hands of the Conservative leadership, the Coalition would have become extremely fragile, and might have collapsed. Clegg would have been an impossibly stroppy partner to Cameron, and might well have lost any authority to keep his party on board. The Coalition breathes slightly more easily.
This is extremely limited comfort for Cameron and George Osborne, yet to prove themselves convincing election winners as leaders. They face a dual nightmare. The Liberal Democrats have shown they can retain the seats that the Conservatives are targeting in the south, while having much less success in Labour’s target constituencies. From the right UKIP strides on, even though Cameron has offered an In/Out referendum on Europe. Tory MPs even further to the right of the leadership have been stirring for some time. They will stir more now. The senior MP, David Davis, warned of trouble if the Tories came third. A formidable operator, Davis does not make such warnings lightly. There will be trouble.
He is by no means alone in a parliamentary party as restive as Labour’s used to be in the 1980s. Cameron will be under immense pressure to deliver something for them, but given that he is already the most Euro-sceptic leader in the party’s history, implementing spending cuts deeper than Margaret Thatcher’s and reforming public services in a way that she would have regarded as too right wing it is not clear what else he can do.
There will be quite a lot of introspection in the Labour party too. Coming fourth is hardly a triumph. Ed Miliband faces a tactical dilemma. Does he do and say very little on the assumption that a divided right cannot win the next election? Or does he say much more in order to make inroads in the south of England? Expect some so called Blairites to brief that they need to do much more to reassure voters in Eastleigh and elsewhere.
By-elections are not a reliable guide to general election results, but Eastleigh forms the prism through which politics will be viewed until the local elections in May. It is one where the focus will be on Cameron, his Chancellor soon to deliver a budget and their febrile party.