Before making his speech on policy towards Russia in Kiev, Ukraine, later this week David Miliband would do well to ponder some wise advice from a great predecessor. Lord Salisbury, Foreign Secretary and Prime Minister in the days of the British Empire, dispensed immense global power; but that did not mean that he liked playing about with that power.

Faced with proposals for British policy that he understood to be deeply damaging to the interests of other great powers, Salisbury would look his colleagues in the eye and ask simply: “Are you really prepared to fight? If not, do not embark on this policy.”

If the events of the past fortnight in Georgia have demonstrated one thing clearly, it is that Russia will fight if it feels its vital interests under attack in the former Soviet Union - and that the West will not, and indeed cannot, given its conflicts in Iraq and Afghanistan.

Other Western threats are equally empty. Russia itself pulled out of co-operation with Nato. If a real threat is made of expulsion from the G8, Russia will leave that organisation too - especially since a club that does not include China and India is increasingly meaningless anyway. The threat of being barred from joining the World Trade Organisation is a bit stronger - but Russia has done so well economically without membership that this goal too has lost much of its allure.

Moscow has reminded Nato of the importance of Russian goodwill to secure the supply lines of the US-Nato operation in Afghanistan through Central Asia. Alternatively, Nato can become wholly dependent on routes through Pakistan. From where I am sitting, that does not look like a very good move - and where I am sitting at this moment is a hotel room in Peshawar, Pakistan.

By siding fully with Iran, Russia has the capability to wreck any possibility of compromise between Tehran and the West, and to push the US towards an attack that would be disastrous for Western interests - and enormously helpful to Russia's.

However, if only he will take it, Mr Miliband's speech could be a magnificent opportunity to set British policy towards Russia on a footing of sober reality - strengthening Western unity and resolve on issues such as reducing our energy dependence on Russia; but eschewing empty promises and shelving hopeless goals such as restoring Georgian sovereignty over South Ossetia and Abkhazia and forcing Russia to change its Constitution to extradite Andrei Lugovoi, accused of killing the former KGB agent Alexander Litvinenko.

Russia, for its part, will have to abandon or shelve its own hopeless goals such as restoring Serbian sovereignty over Kosovo and forcing Britain to change its laws to extradite Boris Berezovsky and the Chechen leader Ahmed Zakayev.

Above all, Mr Miliband needs to think hard before committing Britain to support Nato membership for Georgia and Ukraine. He should look carefully at the widespread Western belief that Russia “set a trap for Georgia” in South Ossetia. There was no Russian trap. In recent years Moscow has made it absolutely, publicly and repeatedly clear that if Georgia attacked South Ossetia, Russia would fight.

The obvious trap was set by President Saakashvili for the West, and was based on the belief that if he started a war to recover Georgia's lost territories, the West would come to his aid. This didn't work as well as Mr Saakashvili wished, because we have not gone to war for Georgia. On the other hand, every Western government statement offering future Nato membership is an implicit promise that we will do so in future if necessary. How can we make such a promise to a man who tried to involve us in a war without even asking us first?

On Ukraine, Mr Miliband should study carefully a range of reliable opinion polls showing that by a margin of about three to one, ordinary Ukrainian voters are opposed to Nato membership. This is not only because they want good relations with Russia, but because they fear being dragged into disastrous American wars in the Muslim world.

Even when it comes to the wider question of alignment with the West rather than Russia, the Ukrainian majority in favour of the Western line is slim - about 53 to 47 per cent to judge by the last Ukrainian presidential election. We should have learnt by now from the ghastly examples of Bosnia and elsewhere that a narrow numerical majority is simply not enough when existential national issues are at stake.

In other words, it is Nato's eastward drive, not Russian ambition, that is the greatest threat to Ukrainian stability and unity. A realistic British policy towards Ukraine should mean a genuine commitment to help it to develop economically, socially and politically in ways that will gradually draw it closer to the West and may one day make European Union membership possible. Under no circumstances should it mean plunging Ukraine into a disastrous crisis for the sake of a Nato alliance that cannot and will not defend it anyway.

Viewing this conflict from Pakistan gives some interesting perspectives. The first is the absolute insanity of the West's stoking a crisis with Russia while facing such intractable problems in the Muslim world.

It is also striking that the Pakistani media have been very balanced in their coverage of the crisis, despite their traditional hostility to Moscow.

Is this because they have suddenly fallen in love with Russia? Not a bit. It is because when it comes to international lawlessness, bullying and aggression, they no longer see a great difference between Russia and America. The moralising of Western leaders, therefore, no longer cuts much ice in Peshawar - or anywhere else much outside the West itself.

Anatol Lieven is a professor at King's College London and a former Times correspondent in the Soviet Union

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