By sending troops into the Ukraine, (others than those stationed there by agreement) Putin has broken international law. That does not depend on the Budapest Memorandum. It would be a breach of international law whether the Budapest Memorandum existed or not. The effect of the Budapest Memorandum is rather to oblige the US and the UK to do something about it.

The existence of civil disturbance in a country does not justify outside military intervention. That it does is, of course, the Blair doctrine that I have been campaigning against for 15 years, inside and outside government. Putin of course opposes such interventions by the West, in Iraq, Syria or Libya, but supports such interventions when he does them, as in Georgia and Ukraine. That is hypocrisy. There are elements on the British left who also oppose such interventions when the West does them, but support when Putin does them. You can see their arguments on the last comments thread: fascinatingly none of them have addressed my point about Putin’s distinct lack of interest in the principle of self-determination when it comes to Chechnya or Dagestan.

The overwhelming need now is to de-escalate the crisis. People rushing about in tanks and helicopters very often leads to violence, and here Putin is at fault. There was no imminent physical threat to Russians in the Crimea, and there is no need for all this military activity. Ukraine should file a case against Russia at the International Court of Justice; the UK and US, as guarantor states, can ask to be attached as guarantor states with an interest in the Budapest Memorandum . That will fulfil their guarantor obligations without moving a soldier.

The West is not going to provide the kind of massive financial package needed to rescue the Ukraine’s moribund economy and relieve its debts. It would be great if it did, but with western economies struggling, no western politician is in a position to announce many billions in aid to the Ukraine. The chances of Ukraine escaping from Russian political and economic domination in the near future are non-existent – the Ukrainians are tied by debt. That was the hard reality that scuppered the EU/Ukraine agreement. That hard reality still exists. The Association Agreement is a very long path to EU membership.

Both Putin and the West are reacting to events which unfolded within Ukraine. Action by the West was not a significant factor in the toppling by Yanukovich – that was a nationalist reaction to an abrupt change of political direction which seemed to be moving Ukraine decisively into the Russian orbit. Ukrainians are not stupid and they can see the standard of living in former Soviet Bloc countries which have joined the European Union is now much higher . Anybody who denies that is deluded. Of course western governments had programmes to encourage pro-western tendencies in Ukraine, including secret operations. It would be naïve to expect otherwise. Anybody who thinks Russia was not doing exactly the same is deluded. But it is a huge mistake to lay too much weight on these efforts – both the West and Russia were taken aback by the strength and speed of the political convulsions in Ukraine, and everybody is still paying catch-up.

Which is why we now need a period of calm, and an end to dangerous military adventurism – which undeniably is coming primarily from Russia. Political dialogue needs to be resumed. It is interesting that even the pro-Russian assembly of Crimea region has only called a referendum on more devolved powers, not on union with Russia or independence. However I still maintain the best way forward is agreement on internationally supervised referenda to settle the position. The principle of self-determination should be the most important one here. If any of the regions of Ukraine wish to secede, the goal should be a peaceful and orderly transition. Effective military annexation by Putin, and insistence by the West that national boundaries cannot be changed, are both unproductive stances.