For much of American Jewry, the coming weekend could well be called Shabbat MLK. Its parasha is the "I Have a Dream" speech, and its divrei Torah concern the glory days of the civil rights movement. Indeed, any synagogue or community center with a conscience, or at least the pretense of one, has long ago planned its special programs for the national holiday on January 15 commemorating the birthday of the Rev. Martin Luther King Jr. I'm part of one such event myself. So let us agree that, yes, it is all well and good for American Jews to give themselves this occasion to bask in the reflected martyrdom of the closest thing to a saint our nation has produced. And, yes, the holiday provides an appropriate occasion to recall those from our own tribe who toiled most selflessly in the cause of black equality - the civil-rights attorney Jack Greenberg, the theologian Abraham Joshua Heschel, the King aide Stanley Levison and the philanthropist Julius Rosenwald. In the midst of our celebration, however, we ought to stop extolling ourselves for an investment of tikun olam that largely ended 40 years ago and consider the alliance that cries out for the Jewish commitment to social justice right now. I am referring to a Jewish-Latino alliance, one that should stir our collective memory as disparaged immigrants and economic scapegoats. Even as the American economy precariously floats on a false high from a housing boom that is already collapsing and tax cuts resulting in record deficits to the federal budget, a mood of financial discontent and blame-laying is building. Republican candidates for Congress last November seized on immigration restriction as their pet issue, and many of the victorious Democrats combined their criticism of the Iraq war with protectionism on foreign trade. President George W. Bush, never one to miss out on a wedge issue, reversed what had been his admirably balanced approach to the immigration issue and had federal agents conduct several high-profile raids of factories employing illegal immigrants, most of them Latino. One of the popular-culture phenomena of the moment, terrifically described by Ken Auletta several weeks ago in The New Yorker, is the reinvention of CNN's formerly pro-business anchorman Lou Dobbs into the nightly nativist, chocking his broadcast with reports on how foreigners are stealing jobs from Americans and undermining the middle class. FOR A Jew to live amid this climate is to be reminded of the venomous opposition our forebears faced 70 or 80 years ago. To the cultural nativists who succeeded in slamming closed the golden door of immigration in 1924, Jews were an unassimilable, irreducibly alien presence. To the economic nativists seeking culprits for the genuine distress of the Great Depression, Jews were the secret profiteers, supping well while others starved. Think of Lou Dobbs as our own time's Father Coughlin, who was so dangerous because of his genius at combining legitimate populism with race hate. The black-Jewish alliance has won its victories - the landmark civil-rights laws of the 1960s, the acceptance of diversity as a centerpiece of organizational life. Certainly, issues and bills and campaigns will continue to rely on this partnership, since Jews remain the most dependably liberal sector of white America. But the leading moral cause today among domestic issues is the preservation of the United States as a society open to and embracing of immigration. In practical terms, this means creating a rational route to citizenship for the millions of illegal immigrants. They inhabit a netherworld, holding jobs that Americans cannot or will not take while having to pretend they do not exist. In the 21st century, the successor to Ralph Ellison's invisible man is now a landscaper named Raul or a maid named Flora. Because Latino immigrants are so numerous, and because their Spanish language is becoming ever more ubiquitous, they are the object of nativist fury. But that fury, if transformed into punitive policy, would surely affect the Indian computer engineer and the Russian professor, too. History tells us that the road to immigration restriction in the 1920s began with bans on Japanese and Chinese. In the wake of those laws, the ranks of the undesirable were expanded to include such Eastern and Southern European groups as Jews and Italians. It is worthy and laudable that so many American Jewish individuals and institutions have put their efforts into the Darfur issue. Compassion and mobilization should not be seen as finite resources. Yet we are missing our moment in not connecting to the large and growing Latino population around the immigration issue. Perhaps, at some of the events this weekend, Jewish audiences will read or hear Martin Luther King's famous "Letter from Birmingham Jail." In it, he is answering a number of moderate clergymen, including at least one rabbi, who have criticized him for holding civil-rights marches and other forms of direct action. What King tells them, in essence, is that the freedom movement is harmed less by the overt, violent opposition of racists than by the complicit disengagement of decent people. Let's hope that as Jews we will have some alliance with Latinos worth honoring decades from now, instead of remembering our unconscionable detachment. The writer is a professor of journalism at Columbia University.