Dennis Showalter, writing in 1975, defended "Starship Troopers", stating that the society depicted in it did not contain many elements of fascism. He argues that the novel does not include outright opposition to bolshevism and liberalism that would be expected in a fascist society. Others have responded by saying Showalter's argument is based on a literal reading of the novel, and that the story glorifies militarism to a large extent. Ken Macleod argues that the book does not actually advocate fascism because anybody capable of understanding the oath of Federal Service is able to enlist and thereby obtain political power. Macleod states that Heinlein's books are consistently liberal, but cover a spectrum from democratic to elitist forms of liberalism, "Starship Troopers" being on the latter end of the spectrum. It has been argued that Heinlein's militarism is more libertarian than fascist, and that this trend is also present in Heinlein's other popular books of the period, such as "Stranger in a Strange Land" (1961) and "The Moon is a Harsh Mistress" (1966). This period of Heinlein's writing has received more critical attention than any other, though he continued to write into the 1980s.