While there debates reflect the diversity of contemporary scholarship on international affairs, there are also obvious signs of convergence. Most realists recognize that nationalism, militarism, ethnicity, and other domestic factors are important; liberals acknowledge that power is central to international behavior; and some constructivists admit that ideas will have greater impact when backed by powerful states and reinforced by enduring material forces. The boundaries of each paradigm are somewhat permeable, and there is ample opportunity for intellectual arbitrage.