No Indian prime minister since Jawaharlal Nehru came into office with warmer feelings about China than Mr Narendra Modi. None was ever so wary about the world’s second-biggest military power and economy, as he seems to be these days.

Last week’s visit by the Indian leader to Washington to consummate what could be the defining global partnership for the next half century underscores several impulses, starting with the natural gravity towards each other of two pluralistic democracies with deep traditions of entrepreneurship and innovation.