This chapter depicts the role of climate sceptic think tanks in the United States. Located in a competitive, adversarial and increasingly polarized knowledge regime, close networks between conservative pressure groups, the Republican party, wealthy donors and a conservative media ecosystem provide funding for several well established, staffed and funded think tanks. The chapter shows how a “conservative countermovement” and its flagship think tanks such as the “Heartland Institute”, the” Cato Foundation” or the “Competitive Enterprise Institute” successfully contested climate science and was able to halt or delay comprehensive climate politics.