If Russia is expelled from the Swift banking messaging system, that would be serious economic warfare against Putin.

Because Thursday’s decision by the US Treasury to make it almost impossible for Russia’s two biggest banks, VTB and Sperbank, to do any business with US institutions or use US infrastructure to process dollar payments will potentially disrupt tens of billions of dollars of Russian financial transactions every day, much of it related to its huge oil and gas industry.

This combined prohibition on international transfers by Russian banks and the US embargo on dollar clearing for them would in theory generate a massive negative economic shock for Russia, that would rapidly impose serious hardship on Russian people.

The big question of course is whether this would start to amplify Russian popular opposition to Putin, or would generate greater popular patriotic anger against the west.

Either way it would be the financial version or shock and awe. Though to repeat what I said earlier, it will be expensive for us too – because it is not at all clear to me how Germany and other EU countries would pay for the huge volumes of Russian gas they need to keep the lights on, their factories running and their homes warm.