Leading article: The coalition experience starts here

A coalition government headed by two relatively young leaders will take a little getting used to, in appearances, even before they get to grips with substance. Their joint press conference yesterday had something of the twin-anchored news bulletin, if not quite the comedy talk-show, about it. From now on, this is a double-act that both David Cameron, and his Liberal Democrat deputy, Nick Clegg, would be advised to invoke sparingly.

Yet the personal rapport and relaxed bonhomie on display yesterday set a pleasing and optimistic tone that contrasted sharply with the tired earnestness of the outgoing Labour government. And while, after 70 years in abeyance, the art of governing in coalition will probably take practice, personal compatibility and a sense of common purpose should help things along. If these start to falter, they could be in trouble.

What is fast becoming apparent, however, is the effort already invested by both men in this joint endeavour. The coalition agreement – a final, more detailed, version of which is promised – is an impressive piece of work for the scant four days it spent in gestation. It is far too early to agree with Messrs Cameron and Clegg that the country is entering an age of "new politics". After all, Mr Cameron's earlier vow to banish "Punch and Judy politics" soon foundered. But the detail of the agreement, and the acknowledgement that in some areas – nuclear power, the marriage tax break and a few others – there will be no agreement and none is expected, shows that the new Prime Minister intends to have another go at a more civilised way of doing politics. We shall see whether this can improve the atmosphere in the Commons. We hope it does.

Civility is a start. So, in more areas than we might have expected, are the policy compromises set out in the coalition agreement and implicit in the first Cabinet appointments. The Liberal Democrats have been given Energy and Scotland. But with Vince Cable becoming Business Secretary and David Laws chief secretary to the Treasury, the wings of the new Chancellor, George Osborne, are clipped.

Mr Cameron may also have appointed more Tory moderates than he would have done, unconstrained by coalition. Kenneth Clarke as Justice Secretary is one, but so is Theresa May – who once spoke of the "nasty party" – as Home Secretary. With William Hague as Foreign Secretary and Liam Fox at Defence, "abroad" looks like the single enclave of Conservative hawks. But foreign and security policy will not be the exclusive preserve of these offices; it will also come under the new National Security Council. And the language on Europe in the coalition agreement is less shrilly Eurosceptic than many Conservatives might have hoped.

The crispness of the agreement conveys a welcome air of urgency and efficiency – an impression reinforced by yesterday's swift announcement that Heathrow will not get a third runway. And while many key decisions have been delegated to commissions, this may not be a bad thing, if it promotes technocratic solutions above dogma. The agreement also serves as a reminder of the common ground that genuinely exists between the Liberal Democrats and a certain stamp of Tory. The "great repeal" of superfluous legislation, the cancellation of ID cards, and the restoration of civil liberties are to be applauded, and the coalition must be held to its word.

There must be grounds for concern at the speed with which the new government intends to start cutting the deficit and what sacrifices might be entailed – a key point conceded by the Liberal Democrats. Iain Duncan Smith's appointment to Work and Pensions may also presage a harsher approach to social welfare than we, and many Liberal Democrats, would favour. But the IDS of today is not the narrow right-winger who briefly and unhappily led the party. Like Michael Gove, who takes over Schools, his thinking goes beyond conventional party lines. We could also have wished for a more wholehearted embrace of electoral reform than the promised referendum on alternative voting.

But for coalition government to work, both sides have to compromise, and that includes the Liberal Democrats. Indeed, their commitment to proportional representation, which would make more common the sort of coalition being tried out here, obliges them to show that they can operate as responsible, if junior, partners. One day is far, far too early, to predict success or failure. Sooner or later tensions will test the solidity of the arrangement. As a start, though, it looks more promising than might have been expected; a project that does not deserve to be written off prematurely.