The International Baccalaureate (IB) has undergone rapid growth and largely unhindered expansion over the past four decades. It has moved beyond its European nexus and the three IB programmes now have a relatively large presence in the USA, especially among public high schools. The IB gathered federal funding in 2003, and a concerted attack has subsequently emerged from a vast array of ultra-conservative agencies and commentators who denounce the curriculum as federal interference, and fundamentally "un-American". This paper explores the complex nature of this "culture war" and reveals the key issues and protagonists.