Tirman points out that agricultural land owners were politically dominant in Iran, well into the 1960s and the monarch, Reza Shah's aggressive land expropriation policies—to the benefit of himself and his supporters—resulted in the Iranian government being Iran's largest land owner. "The landlords and oil producers had new backing, moreover, as American interests were for the first time exerted in Iran. The Cold War was starting, and Soviet challenges were seen in every leftist movement. But the reformers were at root nationalists, not communists, and the issue that galvanized them above all others was the control of oil." The belief that oil was the central motivator behind the coup has been echoed in the popular media by authors such as Robert Byrd, Alan Greenspan, and Ted Koppel.