Christian privilege
The concept of hegemony describes the ways in which a dominant group, in this case mainly U.S. Protestant Christians, disseminate their "dominant" social constructions as common sense, normative, or even universal, even though most of the world's inhabitants are not Christian. Christian hegemony also accepts Christianity as part of the natural order, even at times by those who are marginalized, disempowered, or rendered invisible by it. Thus, Christian hegemony helps to maintain the marginality of other religions and beliefs. According to Beaman, "the binary opposition of sameness/difference is reflected in Protestant/minority religion in which mainstream Protestantism is representative of the 'normal'".
Hegemonic stability theory
Hegemony demands power, which is defined by British scholar Susan Strange as the ability of one party to affect outcomes such that their preferences take precedence over the preferences of other parties. The question of whether the United States is still a hegemon is tied into whether or not it has lost power. 
Keohane sees power as tied into resources and production. The US GDP is now lower relative to others as there are growing economies with considerable amount of GDP such as BRIC countries. This implies a loss or decreased power of US as a hegemon.