The recent Supreme Court decision in Saenz v. Roe struck down a California welfare law that imposed residency requirements on recent arrivals to the state. Invindicating the mobility rights of migrants, the Court breathed new life into the Fourteenth Amendment's Privileges or Immunities Clause. This Article suggests that,however misconceived the decision might appear from the perspective of welfare law, it usefully serves to promote a common American identity on which nationalistsentiments crucially depend. The core nationalist symbol for Americans is the idea of constitutionally-protected liberties that I call liberal nationalismA liberal nationalist understanding of the Privileges or Immunities Clause has four implications for constitutional interpretation. First, it suggests that the mobilityrights the Saenz court upheld deserve the high degree of protection they received in that case. Second, the argument from nationalism offers an explanation for caseswhere the Supreme Court has been faulted for failing to protect national symbols such as the flag. More than the flag, constitutional liberties are a national symbol forAmericans, and in upholding the right to deface the flag on free speech grounds, the Court has merely preferred one patriotic symbol to another. Third, a nationalistperspective suggests that basic liberties should enjoy constitutional protection at the national level and should not be entirely returned to the states. But for the argumentfrom nationalism, a strong case could be made for a very thin set of national constitutional liberties, or even for state opt-out rights. Finally, nationalist concerns suggest aneed for caution before removing contentious issues from political deliberation by turning them into constitutional rights. In politics, there are only winners and losers, andthere is no great shame in being a loser; but in American constitutional law the losers can be faulted for a want of loyalty to core American values, and this must weakenAmerican nationalism.