Paul Mason has made an important contribution to the debate on the left about Brexit. It is an important contribution because Mason is the left’s most militant supporter of the EU: an anti-democratic, capitalist organisation which has become a pillar of globalisation and a driver of inequality. His piece was full of the usual McCarthyite tactic of guilt by association against those who oppose the EU. Mason’s attack on Eddie Dempsey, an anti-fascist trade unionist, was a classic example of this. It is vital that we move beyond this kind of politics on the left.