Leading article: A stout defence that still does not allay all qualms

Yesterday's debate on military action in Libya was essentially a catching-up exercise, following the fast-paced events of last week when the UN Security Council vote, the Prime Minister's Commons statement, the Paris meeting and the first UN-authorised air strikes succeeded each other with scarcely a pause for breath. Nor was there ever any doubt about the result; with scant opposition from any quarter, the vote was always a formality.

The one regret was that MPs had not had the chance to express their views before British planes went into action. Given the imminence of the threat to Benghazi, and the choice between ritual speeches in a near-empty chamber and yesterday's more substantial airing of views, however, the timing was defensible. And an airing of views was necessary, if not for the House, then for the country at large – where a concerned public surely has at least as many questions as their elected representatives.

Not for the first time in his short premiership, David Cameron showed himself to be a fortunate politician – fortune, as he might say, favouring the brave. Time and again, he was able to stress the urgency with which action had to be taken, the humanitarian imperative and the UN Security Council mandate that conferred legality. It was, he – and practically every other speaker – noted in this respect, a situation quite different from Iraq. As if to underline the distinction further, the Government released the full text of its note on the legal basis for the deployment.

He was fortunate, too, in the wholehearted endorsement supplied by the leader of the Opposition, Ed Miliband – who cited his own family's history and the Spanish Civil War – and by heavyweights, such as Sir Malcolm Rifkind and Sir Menzies Campbell, speaking from the backbenches. Sir Menzies, who contrasted his dissenting vote in the Iraq debate with his backing for the Government on Libya, described the international action as "necessary, legal and legitimate". What would Tony Blair have given to have had the House in such a supportive mood?

Any tentative words of warning came almost exclusively from the nether regions of the Labour benches. Yet the questions asked, and the misgivings expressed, deserved their hearing, and on occasion better answers than they received. The combination of Mr Cameron's quiet confidence and Mr Miliband's sombre agreement was seductive. It was also hard, if only for lack of contrary evidence, to challenge the Prime Minister's premise that, if action had not been taken, "Gaddafi would have rolled up the whole of his country in the next 24 to 48 hours".

For the start of the deployment, the Government clinched its case. It was on far shakier ground over what happens next. Is there or is there not an intention to depose Colonel Gaddafi? The head of the UK armed forces, Sir David Richards, had earlier stated categorically that he was "absolutely not" a target – but what if he contrives to hang on? And how truly international is the force? Mr Cameron reeled off a list, but skated over the conspicuous lack of Arab countries, and the head of the Arab League's misgivings about what a no-fly zone would entail. The "protection of Libyan civilians" wore a bit thin as a definition of the mission's overall success.

Probably a more faithful reflection of the qualms in the country generally came from the former Labour defence secretary, Bob Ainsworth – not the only ex-minister to have gained in stature out of office. Clearly scarred by the Iraq experience, he said he was a "late and very reluctant supporter" of the action in Libya. As the operation encounters difficulties, even setbacks, as it surely will, that is a strain of opinion the Government will have to keep constantly in mind.