Resource nationalism is a phenomenon that has troubled American oil companies in many parts of the world, from Venezuela to Russia. They are not used to being confronted by it at home.

Yet that is what is happening now over plans to export liquefied natural gas from the US. When the FT reported last week that ExxonMobil, ConocoPhillips and BP were working towards a preliminary agreement on a $40bn-plus project to export LNG from Alaska to Asia, Ed Markey, a Democratic Congressman from Massachusetts, immediately denounced it as “a threat to American manufacturers, farmers and families”.

Mr Markey is often outside the mainstream of US politics. On the issue of LNG exports, though, he has a wide range of allies, including both environmental campaigners and some businesses.