Americans have an almost blind faith in the melting pot. Not without reason. Our greatest national achievement is fashioning a common identity out of a wide variety of races, nationalities and ethnic groups.

The melting pot melted and we became (with a few lumps) one nation and one people. We did not create a perfect world, but we became a unified nation with a common identity, common language and common allegiances. E Pluribus Unum (From Many, One) is both a promise and a challenge.

Today, that unity is at risk. Immigrants make up more than 10 percent of our population, which has only happened once before in our history, and they are disproportionately Spanish-speakers who can (and do) maintain contact with the old country. We have never taken so disproportionate an amount of immigrants from one linguistic group.

Meanwhile, our own assimilative demands have also been dramatically reduced. Arthur M. Schlesinger Jr., one of the great liberals of my lifetime, warned: "Ethnic ideologues ... have set themselves against the old American ideal of assimilation. They call on this republic to think in terms not of individual but group identity and to move the policy from individual to group rights. They have made a certain progress in transforming the United States into a more segregated society. They have filled the air with recrimination and rancor and have remarkably advanced the fragmentation of America."

So the numbers, the proximity, the incessant flow of Spanish-speaking immigrants, year after year, are building up a bilingual, bicultural society within our society. The tradition that people would drop old loyalties and join us in our polity is disappearing under these pressures. Now some immigrants can vote for both president of Mexico and president of the United States (the latter in either English or Spanish), and we have abandoned the idea that we "foreswear all other allegiances."

We are backing into becoming a bilingual, bicultural society despite the fact that there are no happy models out there. Belgium is talking about splitting its 1,000-year-old country because of the tension produced by its bilingual/ bicultural society. Quebec talks about independence from Canada. In Spain, different language groups set off deadly bombs to force more autonomy. India, Sri Lanka, India, Malaysia, Madagascar and numerous other countries are suppressing rebellion by minority cultural groups. Bilingual/bicultural nations seem to be inherently unstable. Switzerland has a distinct and separate French, German and Roma speaking sections, which is hardly an encouraging example.

I would suggest that our Founders got it right and we abandon our assimilative model of nation-building at our great risk. We have to start to give serious consideration to what policies allow us to form community, live at peace with our neighbors and avoid fragmentation and balkanization.

We do not bond automatically to our neighbors. In many parts of the world, neighbors are viewed as strangers and competitors. A cohesive nation needs a shared stake in the future. It needs a shared language, shared culture, shared norms and values. It needs common goals and common dreams. Nations are forged by commitment, dedication, hard work, tolerance, love and a search for commonalties.

It must understand that all members to a certain degree have a shared fate. To say my fate is not tied to your fate is like saying, "Your end of the boat is sinking." A peaceful nation needs, in short, a unifying social glue, including (but not limited to) a common language.

America's first Puerto Rican- born congressman, Herman Badillo, was the chief sponsor of the Federal Bilingual Education legislation. He now repents his sponsorship because it is balkanizing and "hurts students more than it helps." He warns against a bilingual/bicultural society and demands that Hispanics learn English and "be held to the same high standards as all other Americans."

We can be multi-ethnic but we must have a common language and common culture. We must stay "one nation indivisible."

A sign in a New York classroom late last century warned "Learn English. Be American. Otherwise America will become like the old country."

We are in the process of ignoring that wise advice. What could be the next generation of immigrant success stories is instead bringing a whole second language group to the United States, with its own separate mores, values and culture. We risk instead of having new Americans, having instead "Mexicans living in America" and all history shows that is a prescription for "turmoil, tension and tragedy."

Richard D. Lamm is co-director of the Institute for Public Policy Studies and a professor at the University of Denver. He is chairman of the advisory committee of the Federation for American Immigration Reform, and a former governor of Colorado.