Putin arrives at airport, gets in line at customs.

Customs Officer: “Occupation?”

Putin: “No, just visiting.”

Cabinet has not been a forum for collegiate debate for very many years – as Ken Clarke reminded readers of this site in his interview with Andrew Gimson earlier this week.  But it is still somehow shocking to learn that the crisis in Ukraine was not on the agenda when it met earlier this week (and nor was it discussed).  Perhaps David Cameron believes that it would be impossible to have a productive debate about it with the Liberal Democrats present, and it is certainly true that the long general election campaign is almost all-consuming.  None the less, the lack of discussion, policy drift and implications for defence strategy are worrying some Conservative Cabinet Ministers deeply.

I detect only minority support among them for arming the Ukrainian Government – a course that I am dubious about, since it isn’t obvious what Plan B is if Russia defeats it in the field, which would almost certainly be the case.  And it would be almost an act of war to take Ukraine into NATO.  There is a strong case for believing that Putin wants only to maintain his grip on a country part of which looks to Russia, which is integrated into its economy, which has a corruption-riddled Government and polity, and which was plunged into the present crisis by the EU failing to put its money where its mouth was (in other words, follow up its free trade offer with funds).

None the less, the fact is that Russia is in effect invading and dividing a sovereign European country – and one cannot be certain what Putin will do next.  He will not have concluded in the wake of Minsk 2 – which didn’t acknowledge the presence of Russian troops in Ukraine, let alone set a timetable for their withdrawal – that Angela Merkel or Francois Hollande are forces to be reckoned with.  Cameron, of course, wasn’t even there.  This was scarcely surprising in the aftermath of intervention in Libya and non-intervention in Syria – the latter forced on him by the Commons.  Voters are sick and tired of wars abroad. Tony Blair’s hyped-up case for invading Iraq has poisoned the well of public opinion.

If Putin was Saddam Hussein or Muammar Gaddafi, there would be a case for leaving well alone, and letting the quiet rundown of our defence capacity continue.  But Russia is not Iraq or Libya.  It is in the European theatre.  What it does affects the stability of the continent of which we are part, and defence spending is our insurance policy against instability.  This is not an easy time for Cameron to commit to sticking to NATO’s two per cent defence spending target: the Treasury and voters are on the same side – a formidable combination.  The deficit is stubbornly unconquered.  More spending on defence will mean a deeper scaleback elsewhere.  None the less, he has no prudent alternative to doing so.