Kamala Harris used a Labor Day visit to Pittsburgh yesterday to state that as president she would block Nippon Steel’s proposed $15 billion acquisition of US Steel. Biden did before her, and Trump has already said the same thing. So the bid looks doomed, which is ironic given all three politicians claim to be acting in American workers’ interests yet no one else is offering a comparable investment. ($15 billion represented a 40 per cent premium on USS’s market value when the offer was announced last year.) Another irony is that Nippon’s principal hired gun in this saga is Mike Pompeo, Trump’s ex-Secretary of State, who says quite reasonably the US needs to be open to foreign direct investment. What happens when it isn’t is plain to see at the other end of must-win Pennsylvania, where the black stacks of Bethlehem Steel haven’t fired since 2003.