Abstract: This Essay examines independent constitutional interpretation from the bottom up. It focuses on San Francisco's recent challenge to the California ban against same-sex marriage and the judicial response it provoked in Lockyer v. City & County of San Francisco. The Essay argues against the conventional view that cities either have no distinctive role in interpreting the Constitution or that their interpretations should be considered suspect, even dangerous. But it also contends that cities should generally be permitted to decline to enforce state laws on constitutional grounds, or to challenge their constitutionality in court, only when they do so in order to expand the scope of local policymaking discretion. Thus, the Essay concludes that the problem with San Francisco's disregard of California's marriage laws was not (as the California Supreme Court suggested in Lockyer) that its action was too localist, but rather that it was not localist enough. San Francisco was not seeking freedom from state law so that its officers could adopt a distinct, local marriage policy for San Franciscans. Instead, the city claimed that higher law required all local officers to grant, rather than deny, licenses to same-sex couples seeking to marry. Thus, while San Francisco may have seemed to strike a blow for city power when it took the Constitution into its own hands, a deeper consideration of the controversy suggests that advocates of decentralization should have little reason to cheer the city's actions.