Harvey Klehr, professor of politics and history at Emory University, in his 1988 book Far Left of Center: The American Radical Left Today said that IPS "serves as an intellectual nerve center for the radical movement, ranging from nuclear and anti-intervention issues to support for Marxist insurgencies" [REF].
In his book The KGB and Soviet Disinformation: An Insider's View Ladislav Bittman, a former Státní bezpečnost[REF] agent who worked in misinformation operations, claimed that the IPS was part of the Soviet intelligence network [REF].