If there is a theory that underpins US-led policies on global oil transportation, look no further than former British prime minister Boris Johnson.

He was the champion of the political doctrine that came to be known as “cakeism” — the idea that complex political decision-making could be a zero-sum game with lots of benefits and no downside.

“My policy on cake is pro having it and pro eating it,” he once said in a statement that became symbolic of his policy on leaving the European Union.