So we're to have a Cameron government, even though its composition seems as yet uncertain. There have already been inevitable grumblings - ironically from the very media that wanted him out immediately - that the outgoing premier's abrupt departure may have left his rival in the lurch given that Liberal Democrats have yet to ratify their deal with the Conservatives. It's true that we could have done with a more leisurely transfer, but the pressure on the Prime Minister to go even before an alternative Administration was ready had reached ludicrous proportions.
Commentators anticipate a full Tory-LibDem coalition rather than the alternative scenario of a Conservarive-only minority government with Liberal Democrat support on confidence votes. This should be greeted with a collective sigh of relief from all who hope not to see a repeat of the Conservative excesses of the 1980s. As head of a coalition government, Mr Cameron will have to take his allies' views into account on day-to-day policy matters rather than going it alone and presenting the Commons with the choice of "back me or sack me", as under the "confidence and supply" option.
The new government will command a healthy majority of 83 over all other parties in a House reduced to 645 by the absence of the five Sinn Fein representatives. This should be enough to override likely rebellions on either the Tory right or the LibDem left - a luxury unavailable to the proposed alternative of a Liberal-Labour-Nationalist "progressive alliance".
Numerically, the Conservative-LibDem bloc will be strong. But ideologically, it faces formidable challenges. Liberal Democrat supporters largely consider themselves heirs to the non-socialist progressive centre-left, a stance far removed from core Tory philosophy. Mr Cameron has done much to smooth Conservatism's rough edges, and may well be the nearest to a "One Nation" Tory electable by his backbenchers since the party's abrupt move to more hard-line ideological stance under Mrs Thatcher. But Tory values remain fundamentally at odds with LibDem notions of "social justice".
That said, a Cameron-Clegg alliance can be workable. It won't be easy. Conservatives will have to abandon some of their cherished ideals of minimising the tax burden on the more affluent classes who they see as the nation's economic drivers. LibDems have already had to accept that Proportional Representation in parliamentary elections - their goal for decades - will be off the agenda for the duration. They are reported to have extracted an agreement to pursue an increase in the income-tax threshold, but that will be phased in as government finances permit, and may not be achieved within the lifetime of the present Parliament. On the key question of whether to slash £6bn from public spending this year or next, when the economy may be better placed to survive such a measure, the Tories seem to have had their way, provided there's no marked economic deterioration beforehand. But further savage cuts may come later rather than sooner, which cannot but be favourable to the country's growth prospects in the next 18 difficult months.
The greater risk is faced by Liberal Democrat leaders: if they fail to act as a brake on full-blooded Conservative social policy they may yet face a ferocious backlash from their own voters at the next election. Their party is already poorly-placed financially to contest another contest, and their hope must be that they can restrain their partners' impulses sufficiently - and for long enough - to position themselves as the party which tamed the Tory beast and delivered financial stability without concentrating the costs on the least advantaged. If they fail to deliver that, Labour will be the big winners, fighting not one but two parties tainted by their support for a government of cuts at the expense of the poor.