In the past Democratic candidates with appeal to one part or another of the left of the party were not old men. Eugene McCarthy was 52 in 1968, George McGovern 50 in 1972, Edward Kennedy 48 in 1980, Jesse Jackson 42 in 1984 and 46 in 1988, Bill Bradley 57 in 2000, Howard Dean 56 in 2004, Barack Obama 47 in 2008. All but Jackson were old enough to have experience in government (and an impressive war record in McGovern's case) and young enough to be in vigorous good health.

Compare and contrast with Bernie Sanders, who turns 75 in 2016 — or with one of the subjects of my column on the strange death of the center-left, with Jeremy Corbyn, whom seems likely to be chosen next months as the leader of Britain's Labour party at age 66. Both these men are attracting crowds of Millennials, people too young to remember the implosion of socialism in the era of Ronald Reagan and Margaret Thatcher. Sanders and Corbyn of course don't have that excuse. It's an interesting question: why hasn't the left attracted younger leaders?