US energy policy passed a milestone of sorts earlier this month after two companies revealed they had been given permission by the US commerce department to export “condensate”, an ultra-light form of oil, after minimal processing. Unfortunately the broader ban on US crude oil exports imposed after the 1970s Arab oil embargo remains in place. The White House was quick to clarify that the permissions were exceptional. Similar if somewhat less restrictive inhibitions apply to the export of US liquefied natural gas – the fruits of its hydraulic fracking boom. Barack Obama’s administration is resisting the European Union’s demand to include an energy chapter in the transatlantic trade and investment partnership. He should think again. If TTIP is to fulfil anything close to its ambitions, it must tackle energy. Add in the threat Vladimir Putin poses to Europe’s energy security and the case looks unanswerable. The time has come to put an end to US energy protectionism.

The best argument for doing so is economic. US oil refiners have benefited hugely from the 1975 export ban but at the expense of almost everyone else. Those who lose out include US oil producers and consumers as well as European refiners. In the case of the first, producers get a smaller market for their product – they are forced to sell to domestic refiners. Meanwhile US consumers pay global prices at the pump even though domestic oil is currently $7 a barrel cheaper. There is also a growing mismatch between US supply and demand. Many US refineries are designed to process heavy crude from the Middle East and elsewhere. They are ill-equipped to handle the lighter and sweeter crude that comes from the US shale oil boom. America still imports about a third of its oil. But that share is falling rapidly. Unless the export ban is lifted, the US could face the paradox of a glut of light domestic crude in the gulf region, even as millions of barrels per day of heavy oil imports are still coming into the country.

There is also a powerful strategic case. Europe relies heavily on Russian gas pipelines. Mr Putin has shown no compunction about using the threat of cutting supplies – or jacking up prices – as a lever to extort diplomatic concessions. Ukraine and other near neighbours have been the principal victims. There is nothing to stop Mr Putin from threatening Germany and others with similar measures. As the EU comes round to Mr Obama’s agenda of tougher sanctions on Russia, it is strongly in US interests to support its energy diversification. It would also help revive the case for TTIP in Europe by giving governments a stronger case to take to their electorates. At the moment most of the oxygen is taken by those who oppose any deal because of fears of lower US food standards, weaker data privacy protections and so forth. Adding an energy chapter would restore flagging momentum to TTIP’s supporters.