The local election results kill off what had been, until recently, a widely held assumption. In Number 10, parts of the media and, indeed, within a section of the Labour Party there was an unswerving view that Labour could not win the next general election and Ed Miliband would never be prime minister under any circumstances. Labour's strong performance in most of Thursday's contests means that even Miliband's most ardent critics must accept that a Labour defeat is not inevitable when a general election is held. This does not mean Labour will win or is yet on course to do so, but an assumption of unavoidable doom feeds on itself and is fatal. That is no longer part of the political landscape, a significant change.
A party that retakes control of some of the big cities in England and Wales is not doomed. Labour is not performing spectacularly well, but there has been no meltdown as many commentators eagerly predicted before the last election and there has been no schism, as there was in the 1980s, a split that gave the space for Margaret Thatcher to win landslides. The party is in contention as an alternative to the Coalition.
For the two ruling parties, it is the Liberal Democrats, again, who have not even a fig leaf to hide behind for comfort. All the main parties are starved of cash and struggle for members. In order to breathe, they need councillors to keep them going at a local level. In a way that is easily underestimated, a power base in local government is vital. A large factor in the decline of the Conservatives in the 1990s was the collapse of their local government base after the introduction of the poll tax. They needed forces on the ground, but they vanished as council after council fell in the backlash.
For the Liberal Democrats, the third party in national politics, local government has been an even more important life-support system. Used to flourishing locally when governments are in mid-term, they are now being decimated, performing as poorly as in last year's local elections. A hung parliament remains the most likely outcome of the next general election, so the Liberal Democrats may well continue to play a pivotal role at a national level, but, between then and now, a party renowned for its robust internal democracy is going to find the going almost impossibly tough.
Yet for some Conservative MPs, the Liberal Democrats are having too much of a ball, exerting excessive influence within the Coalition. As the scale of Tory losses around the country became clear, a few of them urged a move further right. One cited David Cameron's support for gay marriage as a reason for the poor showing. Others wanted more spending cuts. Some fumed about House of Lords' reform. I doubt if many former Conservative voters headed for the polls determined to punish Cameron because he is too liberal. It is his recognisably right-wing economic policies and the double-dip recession that form the dark backdrop. A declaration from the Tory leader that he was marching further rightwards would have led to more losses.
Nonetheless, a new assumption is taking hold within parts of his party, as flaky as the old one that Labour was inevitably doomed to defeat: that Cameron does indeed need to march rightwards. In itself, this will heighten tensions within the Coalition as Nick Clegg will feel an opposite pressure to shout even louder about any so-called "progressive" policy gains. The plan on both sides of the Coalition in the immediate election aftermath is to show once more that the two parties are working well together with Cameron and Clegg making joint appearances.
I suspect these public affirmations of resolute unity will do both leaders harm and for sure will not lead to a return of the superficially glowing plaudits that greeted the Coalition's early days. Senior Lib Dems in particular have cause for introspection. They are in alliance with the Conservatives to implement an economic policy that is not working, while the alliance is eating them alive. This is not exactly a dream ticket, but they have no obvious ticket to travel elsewhere.
At least Clegg has not suffered a defeat on a desired constitutional reform, as he did last year in the AV referendum. This year it is Cameron who has suffered the setback. He was, rightly, a strong supporter of elected mayors in other big cities outside London. His adviser, Steve Hilton, delayed his departure from Number 10 in order to oversee this revolution. There will be no revolution. The "no" votes were as emphatic as the rejection of electoral reform last year.
Evidently, there is no appetite for figureheads with limited powers in an ambiguous relationship with central government – an ominous warning for a Coalition which is about to introduce elected police commissioners. Miliband must be almost as relieved about the "no" votes as he was about Labour's performance more widely. He was alarmed about the cost of possible by-elections caused by MPs leaving to fight mayoral contests.
In spite of rejections elsewhere, the mayor is an unchallenged addition to the constitution in London. The result of the capital's latest election will dominate today's headlines, although no national leader will credibly claim credit for the outcome or be blamed for it either. London's campaign was sealed off from the national political scene, a landscape that is becoming increasingly treacherous terrain for the two ruling parties.
Labour gains leave Coalition with identity crisis
Boris Johnson passes the winning post – but it was no easy ride to victory
'Red Ken' finally reaches the end of the line
Clegg punished with his party's worst-ever results
MPs turn fire on Cameron after dismal showing
Labour takes power across the country – and Miliband tightens grip on his party
Leading article: A good result, but Labour must beware a false dawn
Steve Richards: Labour (and Ed Miliband) are no longer doomed
Andrew Grice: Bruised and battered, Clegg will struggle to sell Coalition relaunch
Professor John Curtice: Labour's making progress, but it's still some way from No 10
Chris Bryant: The naked and the dead – just a couple of the things you meet while canvassing
Galloway's Respect wins in Bradford again
'Chipping Norton set' desert the Tories
Cities reject Cameron's dream of mayors for all
Salmond setback as Scots nationalists fail in Glasgow