In order to gain a useful understanding of the breadth of Kelsen's interests in political philosophy, it is informative to examine Charles Covell's book titled "The Redefinition of Conservatism" from the 1980s in which Covell engages Kelsen in the philosophical context of Ludwig Wittgenstein, Roger Scruton, Michael Oakeshott, John Casey and Maurice Cowling. Although Kelsen's own political preferences were generally aimed towards more liberal forms of expression, Covell's perspective of modern liberal conservatism in his book provides an effective foil for bringing to light Kelsen's own points of emphasis within his own orientations in political philosophy. As Covell summarizes them, Kelsen's interests in political philosophy ranged across the fields of "practical perspectives underlying morality, religion, culture, and social custom."