Donald Tusk, Poland’s Prime Minister, could not have chosen his words better when he told his countrymen: “We have crossed the Rubicon.” He was speaking after the signing of an agreement with America to base ten US interceptor missiles on Polish soil, ostensibly to protect the West against rogue states such as Iran. To clinch the deal, the US also agreed to boost Poland’s defence with Patriot missiles and to conclude a mutual defence treaty “in case of trouble”.

Trouble came hours later in the form of a direct threat from General Anatoly Nogovitsyn, the Russian deputy chief of staff, who warned the Poles that they should now regard themselves as potential nuclear targets. The Russians believe that the interceptors have nothing to do with Iran but are part of a Western defensive shield that could one day make the Kremlin’s huge stockpile of ballistic missiles obsolete.

Moscow has used apocalyptic language before, and no one is seriously suggesting that Warsaw or Crakow will become smoking ruins any time soon. But the Polish move, and the Russian threat, provide the clearest evidence yet that the six-day Georgian war has spread to Eastern Europe’s ancient fault-lines.

This new East-West contest is likely to intensify. Next week Nato foreign ministers will meet in Brussels to discuss how to respond to the conflict in Georgia. They are likely to reconfirm the decision adopted earlier this year at the Nato summit in Bucharest to open the door for Georgia and Ukraine’s eventual membership.

Vladimir Putin's mastery checkmates the West

Michael Binyon says Russia has been biding its time - but its victory in Georgia has been brutal and brilliant

Multimedia

• Video: stories from the front line

• Pictures: Georgia conflict

BACKGROUND

• Hellraising for the rich: how Osborne met Rothschild

• Oleg Deripaska - oligarch at centre of storm

Related Links

• Nato divided on American call to punish Moscow

• Russia threatens Poland with nuclear strike

• Georgians accuse Russian army of atrocities

Multimedia

• Pictures: Russia-Georgia war

If the West was surprised by the ferocity of Russia’s action in Georgia, the struggle over Ukraine will be far more intense. Many Russians regard their western neighbour as part of their homeland, a view shared by many Russian-speaking Ukrainians. Moscow and Kiev are already locked in a bitter dispute about the future of the Black Sea Fleet base at Sevastopol. Nato membership would exacerbate the row. Any outbreak of violence could have huge repercussions.

Modern wars normally follow a familiar pattern. When the fighting is over, diplomats negotiate a ceasefire, troops retire, peacekeepers are inserted and negotiations begin to prevent renewed hostilities. Georgia’s war over a mountain enclave seems to ignore the trend. This conflict threatens to trigger a struggle that, if badly handled, could consume an entire continent.

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