House Republicans may have dealt a death blow to President Bush’s efforts at “comprehensive” immigration reform, refusing to negotiate a compromise with a Senate bill they claimed amounted to “amnesty.” As Brian Bilbray’s recently successful campaign to succeed the disgraced Duke Cunningham in Orange County, Ca., seemed to show, there is short-term gain to be had for Republicans who talk tough about immigration.

But over the long run it seems unlikely that Americans are going to have much appetite for building an East German-style wall to keep out people whose chief sin is desire for a job, unless there appears to be no other choice. To his credit, President Bush appears to be retooling his immigration reform campaign to stress assimilation. The need to create Americans out of immigrants is something that most people can agree upon.

This was underscored by the instant backlash to photos of Hispanic demonstrators waving Mexican flags during recent marches aimed at protesting the House’s build-a-wall bill. But Bush’s idea of assimilation seems to be both limited and at cross purposes with existing policy. The president focused mainly on the idea that everybody should learn to speak English. He also called for a cadre of volunteers that would teach immigrants about American customs.

But this is a half-hearted approach to the “brutal bargain,” by which immigrants accommodate themselves to the American way of life in return for the opportunities made possible by that way of life. To be credible, Bush needs to declare war on today’s ideology of multiculturalism. If he did, he might find that it resonates strongly with average Americans. One reason for hostility to immigration, whether legal or illegal, is that many people fear we are drifting towards a disunited America, an America riven by ethnic conflict – perhaps even the “Mexifornia” decried by historian Victor Davis Hanson in his book by that title.

Somewhat the same fears were voiced about Italians, Eastern Europeans and others who are now taken for granted as true-blue Americans. Such non-Anglo people were said to lack the habits of democracy that would make them reliable, productive citizens.

That proved untrue. But in the present-day context, in which much government policy actively encourages hostility to democratic capitalism, it’s not an unreasonable concern.

Despite Bush’s pronouncements about the value of a common language, for example, federal voting rules push bilingual ballots. Bush himself favors affirmative action plans that amount to bare-faced ethnic quotas, an invitation for racial spoils systems. And while the No Child Left Behind Act purports to demand higher educational standards, it does nothing to rectify school curricula that vilifies the dead white Europeans who created the American experiment.

The best assimilation policy, of course, is a vibrant economy. People who see opportunity are likely to have a good opinion of the culture that created it. But minimum wages, high taxes and laws that make it tough to hire and fire new employees have helped create a vast underground economy that is made to order for illegal immigration. Undocumented jobs, an outgrowth of the welfare state, are the real story behind undocumented workers. And no doubt there are many who now come to the United States not to work but to avail themselves of the welfare state, with the usual demoralizing, alienating effect. We shouldn’t be surprised if they can fall prey to activist demagogues waving Mexican flags..

The term “assimilation” has fallen on hard times lately. Multiculturalists insist that it’s code for racism, at worst, and lack of respect for “diversity” at best. But assimilation is the balancing principle between a static society and a relatively open, dynamic society. If those who are already here don’t perceive the newcomers as Americans-in-the-making, then we are sowing the seeds of social, political and economic calamity far beyond a few million Mexicans picking fruit in California or raking sand traps in Pennsylvania.

If President Bush is looking for a new war to fight, let it be against the evil empire of multiculturalism.

Mr. Bray writes columns for the Detroit News and RealClearPolitics.com.