Since Donald Trump's election in November 2016 the most common critique of his foreign policy is that it swings a wrecking ball through much of the liberal international order that has been the basis for prosperity and stability across much of the Western world for the past 70 years.

In recent weeks that argument has again come to the fore as a result of his antics at the G7 meeting, including the call for Russia to be readmitted to the grouping, and the launching of a trade war against China.