A former Trotskyist and long-term member of the Socialist Organiser Alliance, researching Hal Draper, Johnson is a co-author of the Euston Manifesto. He was opposed to the 2003 invasion of Iraq. Since 2003 he has worked with Abdullah Muhsin of the Iraqi Workers Federation. Critical of the blanket labelling of advocates of military intervention against dictatorial regimes as neoconservatives in foreign policy, he calls for a "proper consideration of the social democratic antitotalitarianism of Paul Berman, Václav Havel, Adam Michnik, Ladan Boroumand, Kanan Makiya, Azar Nafisi, Bernard Kouchner, Tony Blair, or Gordon Brown" and points out that "neo-conservatives" in the Democratic Party deserve "their share of the credit" for "undermining cynical and self-defeating 'realism' and embracing democracy-promotion."