Robert Kagan (2003) is one of those intellectuals who contributed to the growing salience of academic studies on power. He compared the United States to the European Union and came to the conclusion that the former is a typical hard power whereas the latter can be better defined as a soft power. In his categorization, its immense material power capabilities put the United States in a unique place in power hierarchy and lead Americans to see foreign and security policies from the perspective of military power. The correct answer is D.