The US is a rogue superpower. Its decision last week to renounce participation in the climate agreement reached in Paris in December 2015 underlined this reality. The question is how to respond.

Denial of man-made global warming is an article of faith for many Republicans: Donald Trump’s hostility to action is no idiosyncrasy. But clever lobbying reinforces disbelief. The debate parallels those on the dangers of lead and tobacco. In those cases, too, lobbies exploited every uncertainty. The arguments for action on climate are quite as strong as on lead and tobacco. But obfuscation has again been effective.

American views on the US role in the world also matter. HR McMaster and Gary Cohn, Mr Trump’s advisers on security and economics, have recently written that: “The president embarked on his first foreign trip with a clear-eyed outlook that the world is not a ‘global community’ but an arena where nations, non-governmental actors and businesses engage and compete for advantage. We bring to this forum unmatched military, political, economic, cultural and moral strength. Rather than deny this elemental nature of international affairs, we embrace it.” These, we must remember, are the “adults” in the White House.