Gazprom production facilities in Siberia, Russia. Photograph: Alamy

Europe depends on Russian oil and gas exports, so an embargo may not be practical. But there is another way to apply pressure

Russia is vulnerable to sanctions. Economic weakness caused the collapse of the Soviet Union a quarter of a century ago and – the self-enrichment of the oligarchs apart – not much has changed since. Energy exports to the rest of the world pay for imports of machines and consumer goods. The population is ageing and there has been little industrial diversification.

So, if the west really wants to hurt Vladimir Putin it should slap an oil embargo on Russia similar to that used against Iran. A drop in oil exports would mean Russia would not be able to afford German cars, French wine and Italian designer clothes.

It's not quite that simple. Europe is dependent on Russia for its energy supplies, so an embargo might be a classic example of shooting oneself in the foot, especially if Russia finds a way of sending its oil and gas east to energy-hungry China.

This, though, could not happen overnight, so what the west really needs is a way of hurting Putin that does not hurt itself. Neil Barnett of the Centre for Policy Studies says there is a way of doing this: persuade Saudi Arabia to do the dirty work.

There is a precedent. Angered by the Soviet invasion of Afghanistan in 1979, the Saudis turned on the oil taps, driving down the global price of crude until it reached $20 a barrel (in today's prices) in the mid-1980s. It would take a much smaller drop in the cost of oil – from $107 a barrel currently to somewhere south of $90 a barrel – to cause Russia severe financial and economic damage.

Saudi Arabia is the only producer with the potential to drive down prices in this way and, with much deeper pockets than the Russians, could afford to do so. Barnett believes the Saudis might be up for such a move – which would also boost global growth – in order to punish Putin over his support for the Assad regime in Syria. Has Washington floated this idea with Riyadh? It would be a surprise if it hasn't.