Donald Trump and Jeremy Corbyn are two of a kind

Donald Trump is probably the last person in the world that Jeremy Corbyn would want to be compared with. But there are similarities. In the first Republican presidential debate, Mr Trump showed off the qualities that have made him attractive to so many angry conservatives: straight-talking and aggression. There is a temptation to dismiss him as the silly season candidate. But his polling is unusually high for such a maverick figure. Nothing seems to undermine the love of his fans.

The problem is that for every American who admires Mr Trump, countless others dislike him. His popularity within the conservative base threatens to force other Republicans to indulge in nationalist and protectionist rhetoric, while respect among moderates declines. History is full of such people who capture the heart of a party while driving away the rest of the country. The romance can be so passionate that some supporters will even swear that they do not care about winning elections. Righteous fury is its own reward.

Thinking of Mr Trump in such terms immediately brings Mr Corbyn to mind. He, too, appeals to his movement’s grassroots. He also offers simplistic solutions to complex problems, served up with class-war rhetoric. That two very different parties should be in the grip of a similar phenomenon attests to global dissatisfaction with political leadership. Britain’s Conservative Party, however, has done well to avoid panic. It has understood that elections are still won in the centre ground and countries governed by consensus and economic common sense. By doing all of this, it has been able quietly to get on with radical reforms of welfare. Republicans take note: reason achieves more than angry noise.