National identity has been pivotal to the fortunes of modern states. When channeled in the form of an exclusive and intolerant ethnonationalism, it can drive acts of persecution and aggression. Yet national identities can also be built around liberal and democratic political values, and around the shared experiences of diverse communities. Contrary to arguments that the concepts of national identity and state sovereignty have become outmoded, such an inclusive sense of national identity remains critical to maintaining a successful modern political order. National identity not only enhances physical security, but also inspires good governance; facilitates economic development; fosters trust among citizens; engenders support for strong social safety nets; and ultimately makes possible liberal democracy itself.