One hundred days in, Donald Trump faces a problem: he can rage, but he can't govern

He says it's the "best 100-day start of any president in history", but you can file that along with his boast about crowd sizes and his claim to have won the 2020 election. In truth, the first three months of Donald Trump's second presidency have been calamitous on almost every measure. The single biggest achievement of those 100 days has been to serve as a warning of the perils of nationalist populism, which is effective in winning votes but disastrous when translated into reality. That warning applies across the democratic world - and is especially timely in Britain. Start with…