If Hillary Clinton wins the US presidential election in November, three of the world’s five largest economies will be led by women. Angela Merkel, Germany’s chancellor, Theresa May, UK prime minister, and Mrs Clinton, have all been hailed as role models for women and girls. But the singularity and precariousness of their success raises the question: are women automatically good examples for other women?

“The ability of role models, in portraits and more importantly in the flesh, to influence gender inequality is both encouraging and muddy,” says Iris Bohnet, professor of public policy at Harvard University’s Kennedy School.

Some evidence on the power of role models is overwhelmingly positive. Ms Bohnet cites the Panchayati Raj act, a constitutional amendment in India introduced in 1993, which stipulated that village councils needed to reserve one-third of their seats, and one-third of their council leader positions, for women. Not only did the share of Indian local government posts held by women rise from 5 per cent in 1993 to 40 per cent by 2005, but the new role models the law created had a dramatic impact on families and younger women.