Arnold Schwarzenegger's renunciation of his past support for Proposition 187 confirms that the Austrian's wild tour of the American ideological spectrum has now taken him definitively away from anti-immigrant policies. Democrats can enjoy watching him squirm as he describes the "intensity of prejudice" among his onetime supporters. But the rest of us, including liberals, should stop smirking; we don't know how to talk effectively about immigration either. Two problems stand in the way: Immigration policy has only ever really united Americans when they could talk about it in racist terms, and talking about immigration in terms of class has tended to explode Democratic coalitions.

The last time existing American immigration policy was genuinely popular was in the 1920s, when congressmen could safely say, as Clarence Lea of California did, that "[t]rue assimilation requires racial compatibility" while passing legislation that was supposed to "fix... the type of the American race." It was the golden age of American racism, when Birth of a Nation ruled the box office, Madison Grant's The Passing of the Great Race taught Americans to speak knowledgeably about protecting the Nordic peoples, and the Ku Klux Klan rose in a new and expanded version (now, with extra added bigotry against Jews and immigrants).

The 1924 Immigration Act restricted immigration by imposing quotas based on national origin, on the presumption that some nations were incapable of producing good Americans. It easily passed a Congress dominated by Republicans in both chambers, clearing the House by a vote of 323-71 and the Senate by a vote of 62-6. President Calvin Coolidge gladly signed it; he too thought that "biological laws tell us that certain divergent people will not mix or blend." Immigration restriction won the support of the American Legion, whose commander John Quinn declared in gloriously mixed metaphor that "the melting pot is impotent." It also won the approval of the American Federation of Labor (AFL), whose president Samuel Gompers warned against "racial groups" oblivious to immigrants' "menace to the people of their adopted country."

That was the political genius of the debate over the 1924 law -- it depended on racism, and racism brought Americans together (or enough of them, anyway, to garner wholesale congressional support). This was an innovation, as Gompers noticed: "There is less hostility to enactment of proper immigration legislation in this session of Congress than ever before." Before, Gompers and other labor leaders had tried to sell immigration restriction based almost exclusively on class considerations, and had only ever won with great difficulty.

For decades before World War I, the AFL had supported a literacy test to restrict immigration. The argument was almost purely an economic one, based on working-class interests. Literacy tests had of course been used for racist purposes -- keeping nonwhites out of Natal, in South Africa, or out of Australia -- but those tests required immigrants to read in a language not their own. The American literacy test required that immigrants demonstrate competence in their own language, as a way of hindering the influx of working-class foreigners. It discriminated, in other words, not on the basis of race, but on the basis of class. As President Woodrow Wilson explained in opposing it, the test was "merely a penalty for lack of opportunity," which "constitutes a radical change in the policy of our Nation." Wilson was right -- had the literacy test been more of a racist bill, like the 1882 Chinese Exclusion Act, it would have fit the pattern of popular American immigration policy better. But because it was cast in class terms -- because it was, as The New York Times put it, a "labor exclusion bill" -- it won support less easily.

The literacy test came before Congress repeatedly. Sometimes it passed, but it met presidential vetoes from Grover Cleveland, William Howard Taft, and Wilson before finally passing a Democrat-dominated House and Senate over Wilson's veto in 1917. The literacy test made national leaders nervous. Framed as a protective measure for the least-skilled workers who otherwise had to compete on a global market for their jobs, it did not obviously appeal to other constituencies, and threatened to cost employers money. And insofar as it annoyed ethnic voters, it posed a major threat. As Wilson wrote a Democratic senator, he simply had to veto the bill, irrespective of support for it from within his party: "I myself personally made the most explicit statements at the time of the presidential election about this subject to groups of our fellow-citizens of foreign extraction" -- and Wilson needed their votes. He was right to be nervous, too: Ethnic voters deserted the Democrats at the next presidential election, which made them a political minority for a dozen years.

We can draw a few conclusions from this history:

1. A reactionary, racist argument against immigration might be popular, but as Schwarzenegger has recently discovered, it's immoral.

2. An argument against immigration based on the needs of the workers now living in America will be insufficiently popular, and will also hurt a party that, like the Democrats in 1916 and 1932, relies on the votes of immigrants and their immediate families. Inasmuch as it denies opportunity to those who deserve it, that argument is immoral, too.

3. But an argument simply favoring immigration will not, by itself, strike working people in America as fair.

What to do? Maybe something that Americans used to understand how to pull off -- allowing immigration while spending money to alleviate its impact. The peak years of immigration were also years of devotion to public education and to public health measures, both of which Americans thought would mitigate the effects of immigration. These policies didn't rest on enlightened arguments -- Americans wanted education for assimilation and public health measures to protect them against foreigners they considered disease-ridden -- but the policies were good. Education increased workers' skill levels. Public health measures made it safer to move around the country.

Looking forward, the lesson seems clear enough. By promoting new and broader public services and social outlays as part of a humane framework for approaching immigration, we can adapt Americans to the global economy without compromising basic moral and economic concerns.

Eric Rauchway is the author, most recently, of Blessed Among Nations: How the World Made America. He teaches history at the University of California, Davis.