On a warm Wednesday night, Pasadena's Old Town is full of young couples, many of them "interracial," to use the current jargon. A dark-haired fellow who may well have some Irish ancestors strolls hand-in-hand with a Southeast Asian girl, perhaps the daughter of refugees from Vietnam. Another young man with a thick accent, Russian maybe, jabs the air with his finger as he walks beside a young woman with roots in India or Pakistan. Is this a preview of what America will look like in a few decades? I'm here in California for a conference. This was home until we moved to the Midwest six years ago—and it seems to me that even in that short span, the number of interracial couples has increased greatly. But is this a trend that will remain limited to Los Angeles and a few other urban areas? I don't know, but I am guessing that more and more couples throughout the United States will be crossing racial lines. We haven't begun to grasp the profound impact of the "new immigration" of the last 30 years, the greatest influx of newcomers since the peak years at the beginning of the twentieth century. A recent study reported that 40 percent of the people living in New York City are foreign-born. But the impact of the new immigration is not limited to New York, Miami, Chicago, Los Angeles, and other huge urban centers. Wherever you live today, the girl or boy next door may be from Laos or Bosnia, Mexico or the Philippines. (See the current issue of Mother Jones, for instance, for an article on Mexicans in the U.S. "heartland.")One consequence of this unprecedented intermingling is that barriers which once seemed insurmountable have simply melted away. Not that long ago it was against the law in some states for Asians to marry whites. Now ...