The United States has a liberal citizenship tradition. With the important exception of racial qualifications, which were not fully eliminated from the nationality law until 1952, barriers to citizenship have been low. Since the adoption of the Fourteenth Amendment to the US Constitution in 1868, the United States has maintained a near-absolute rule of territorial birthright citizenship. Naturalisation requirements have been and continue to be satisfied by permanent residents in most cases upon satisfaction of durational residency requirements. Citizenship law has remained stable in recent decades, for the most part insulated from highly charged debates over immigration policy. Restrictionist successes with respect to immigration policy have not translated into tightened access to citizenship. The parameters of citizenship acquisition have been largely uncontested for more than a century and a half. As a historical matter, citizenship’s low profile is attributable to the country’s immigration roots. Immigration to the United States was open until towards the end of the nineteenth century. Those who came to the United States were assumed to stay. The legal assimilation of immigrants …

These have been heady times for those interested in foreign relations law. The last twenty years have seen the field transformed. In the 1970s and 1980s, Vietnam had triggered significant attention on constitutional war powers, but that interest was more political than scholarly. Other foreign relations law issues were debated only at the margins. The Restatement (Third) supplied a largely unchallenged conventional wisdom in the area, even if some of its main points were more aspirational than descriptive. The courts had long been missing in action; though they had been active in the first century or so of the Republic on international law and foreign relations law issues, probably the most important Supreme Court ruling in the area from the second half of the twentieth-century merely served to confirm the judicial timidity. On many of the most important issues of foreign relations, sparse judicial precedents (such as they existed) had no more than oracular application to contemporary questions. Other actors nonetheless managed to achieve constitutional equilibria with little help from the courts or scholars. The …