People are supposed to grow ever more conservative with age. The teenage dreamer becomes the middle-aged pragmatist, who in turn settles into late-life reaction. A curious feature of Joe Biden’s story is that it defies this classical arc. The New Democrat of yesteryear, tough on welfare and even tougher on criminals, is now the party’s most progressive candidate for the White House since the 1980s.  

Nothing makes the point more resoundingly than his economic platform. A President Biden would spend upwards of $2tn on climate change abatement. The money, which doubles up as stimulus for a stricken economy, would not just fund research into clean energy but directly update America’s physical infrastructure.  

There would also be more federal funding for schools in poor areas, for first-time homebuyers, for certain kinds of Social Security recipient. On healthcare, the former vice-president stops short of the left’s dream — Medicare for all — but he would build on the reforms of his old boss, Barack Obama. Taken together, says Moody’s Analytics, his plans call for “an additional $7.3tn in government spending over the next decade”. Neither Mr Obama nor Bill Clinton were quite as ambitious.