Joe Biden’s decision to ban imports of Russian oil increases the economic pressure on Vladimir Putin – but it is not without risk.

On the face of it, the announcement from the White House looks like a bit of a free hit, given the fact that Russia accounts for just 7% of the oil imported by the world’s biggest economy. Three-fifths of Russia’s oil exports go to the EU, only 8% to the US.

Even so, Biden is taking a gamble for three important reasons. The first is that a toughening up of sanctions has given another upward twist to oil prices. American motorists were already paying higher pump prices, even before the latest surge in the cost of Brent crude above $130 a barrel and, as the US president admitted, they will soon be paying even more.

Oil prices are up by 70% since the start of the year and there is no sign of them coming down anytime soon. The Oslo-based consultancy Rystad Energy has predicted a complete ban on Russian oil and gas could send crude prices to $200 a barrel. The previous milestone was the $147-a-barrel peak reached in 2008.

The second risk is that Biden’s action fractures the western coalition against Putin, which in the first two weeks of the conflict has been solid. While support from the UK (phased in by the end of the year) means the US is not going it alone with its ban, other European countries clearly have misgivings. That is hardly surprising, because the EU gets 40% of its gas and just over a quarter of its oil from Russia.

So when Biden said the west remained united in its determination to keep the pressure on Russia, that is not strictly true. The EU, as the German chancellor, Olaf Scholz, made clear 24 hours before the US ban was announced, is worried about its energy security and has decided not to follow suit, for now at least. There is no risk of the lights going out in the US; the same could not be said of every country in Europe.

This dependency on Russian energy creates a third risk, namely that Putin gets in his retaliation first by cutting off supplies. The EU has announced steps to reduce its dependency on Russian oil and gas, and the crisis could well have the effect of speeding up the transition from fossil fuels to clean energy, but in the short term the loss of such a big chunk of its energy supply would result in weaker growth and higher inflation.

While high energy prices eventually prove self-correcting because they tend to lead to recessions, the damage they can cause is considerable. UK living standards are on course for their biggest one-year fall since modern records began in the mid-1950s, with the war in Ukraine putting at risk the post-pandemic recovery. All of which makes it important that sanctions work quickly. The longer the economic war, the higher the cost.