Just look at Ken Livingstone. A few years ago, given a police killing of an innocent civilian, he would have been all over the media shouting "cover up" and "state authoritarianism." Now he's almost mooning in his praise for the Met's Commissioner, Sir Ian Blair, and talks like a Northern Irish judge in his condemnation of officers who leak the facts.
But Red Ken is an "homme pas serieux", as the French would say, which is why Londoners have a soft spot for him. Blue Ken is an homme manifestly serieux, so his decision to distance himself from the euro is a significant move for so strong a europhile.
The distancing, if you read the precise words of the interview in the Central Banker, is more in tone than in words. Minute examination of the wording would find it hard to pin treason to the euro cause upon him. He still believe in the euro. It's only, as he puts it, that he doubts if British membership "is possible for 10 years or more".
But tone is all in politics, as well Ken knows. Well before publication of the interview, "friends of Mr Clarke" were briefing the press of how their man had called for water and would be washing his hands of the euro. His silence since suggests that he is more than happy with the headlines in the Tory-supporting, eurosceptic press. Europe is now bad news as far as British politics is concerned and Ken Clarke, the most prominent europhile, has decided he wants as little as possible to do with it at this stage.
Better in power tempering his party's natural aversion to the Continent than outside shouting alone against the wind, you might argue. Come the prime ministership, if it ever came, and we would have an instinctively pro-European premier determining events.
But it doesn't work that way. Think of Tony Blair, who expressed such a desire to put Britain back at the heart of Europe before he came to power. Since then, on every single major issue, he has done the opposite and kept his and the country's distance from European developments. It's not that he's changed his mind, necessarily. It's just that the politics never work the European way.
There is nothing wrong with seeking the prime ministership. Indeed it would be somewhat suspicious if a senior politicians didn't hanker after the top job. It is one of the ironies of politics that the public wants its leaders to behave as if they were above personal ambition yet would dismiss them as marginal if they really were.
And yet there is a difference, which most of the public readily sense, between those politicians interested primarily in possession and those with a wider vision of the game.
The distinction has come out very clearly in all the documentaries and discussions that have accompanied the 60th anniversary of the end of the Second World War. TV companies have often been criticised for being over-obsessed by the war, but the recent spate of programmes about relations between the victors (Channel 4), the year 1945 (the History Channel) and the post-war occupations (BBC2) have been revelatory.
Besides showing up just how far historians still disagree on who were the heroes and villains of the time, they have pointed yet again to how the failure of understanding and policy early on led to most of the problems following. Churchill's standing goes up as new evidence of Russian ruthlessness emerges and his warnings seem more prescient. Roosevelt and Truman's (as Eisenhower's and MacArthur's) stars are fading, as the archives of Stalin's expansionism and Hirohito's complicity come to light.
One doesn't want to exaggerate the problems of today through false comparison, but Europe is unquestionably at a historic point. On the one side, there are powerful pressures pulling it down and apart, socially as much as economically and politically. On the other, there are huge opportunities opening up in terms of its potential expansion and its place in a globalising world.
The troubles of the euro are obviously about the strains of a one-size-fits-all monetary policy. But, more fundamentally, they are also about the problems of growth, unemployment and activity that now beset the continent and are beginning - should anyone dare challenge the Chancellor's complacency - in the UK.
Ken Clarke's betrayal doesn't lie in his simple appreciation that joining the euro is not on the British agenda for a long time yet, if ever. That is obviously true for the moment, although events could change more rapidly than Clarke's 10-year horizon. It lies in his acceptance, implicit throughout the Central Banker interview, that Britain has no interest or role in what is happening on the continent; that Europe is something entirely separate from us. So long as things are going reasonably well here, we can sit back and look on the continent as if we looking at developments in Patagonia.
There may well be good reasons for seeing Ken Clarke at the head of the Conservatives. He would be good for politics and the party. But there are other ordinary politicians applying for that job. Europe, and its cause in Britain, needs an extraordinary one in its present state. It seems it has just lost one.