What's the true cost of Donald Trump? All the crises around the world that we've no time to fix

We're all having to master a vocabulary that was once the preserve of specialists. Now everyone needs to know their tariffs from their treasuries, their levies from their yields. But there's one more term from the realm of economics that urgently needs to enter our lexicon. Given what Donald Trump is doing to the world economy - and the world - we need to talk about opportunity cost. Put simply, opportunity cost is the value of opportunity lost. It's the benefit you could have had if you had chosen a different path. For an economist, the opportunity cost of the…