The European Council will vote today on the nominee for Commission President. One month of political wrangling on from the elections, it's now certain that Jean-Claude Junker, EPP candidate, will get the nomination because of his majority in the European Parliament. Despite this, Cameron wants an official vote in the European Council rather than concede to consensus in return for some concessions.
What does Cameron get out of this? It may be a principled stand, and it also plays well to the domestic audience to not be seen giving any concessions or backing down (particularly with his backbenchers in the UK Parliament) - indeed Cameron has made this such a personal crusade that it's practically impossible for him to back down now. However, it's not likely to help Cameron's position on Europe for long: just as the 2011 veto failed to change anything and did little to help boost the Conservatives against UKIP, and being outvoted around the Council table is unlikely to inspire confidence in the plan for renegotiation.
The sight of the Swedish and Dutch governments ditching the anti-Juncker alliance also undermines the idea of some type of Northern European Alliance that the UK can be a part of, and even if it did stick together, whether it would be strong enough to push successfully for change. That's not to say that the UK couldn't build such an alliance, or that those countries don't really support (some) of the UK's aims, but the way the UK conducts its diplomacy means that the current "alliance" is really only skin-deep. At the moment Britain seems to identify countries that have a few of the same grumbles and tries to band together just on that issue - but since the EU is basically a series of endless negotiations, in an alliance you need to have strong links over several issues (otherwise allies are less likely to stick their necks out for each other). Without greater coherence and a longer-term attention, the UK becomes less useful to its allies, leading to a weaker alliance. Cameron's blundering anti-Juncker campaign has probably soured some relations and made it more difficult to get allies.
The vote might have another legacy by cracking the history of decisions by consensus. How will this filter into the decisions over other posts? In the short term we'll see a return to consensus as governments fear being isolated by a damaging vote, but the threat of a vote will increasingly hang over the Council table, where even a big country can be outvoted. There may not be more voting, but the European Council may become more majoritarian in character.
After Juncker is nominated and elected Commission President, it will be interesting to see how he will react to Britain's goals (and what job the UK's Commissioner will get!). Cameron has definitely burned all bridges there, but Juncker will still have to react to the increased Euroskeptic representation in the Parliament and the persistent left-wing discontent on the Eurozone. Getting into office is probably the easy part.