Recent history does not suggest that America has such a surplus of presidential talent that it can afford to spurn an audition by a mayor who governs where more than 40 percent of waterborne imports enter the country — through the ports of Los Angeles and Long Beach. Where more than 50 percent of residents are either immigrants or the children of immigrants. Where immigrants from more than 30 nations form those nations’ largest overseas communities.

Garcetti’s immersion in immigration realities gives him standing to warn his party, which is addicted to identity politics, that “people do want a national identity.” We are “not an ethnic nation but a civic nation,” and Democrats must speak to “identity” rather than “identities.” Also, he brings practicality to the ideological argument about so-called sanctuary cities: When a Korean immigrant, who became a citizen and later a Los Angeles police officer, was shot — not fatally — witnesses and others in the neighborhood, many of them likely illegal immigrants, came forward with information that enabled the police to capture her assailant within hours. Such police-community cooperation is, Garcetti says, jeopardized when local police are viewed as closely allied with federal immigration enforcement.