Mex-America: A State of Mind : MIGRANT SOULS <i> by Arturo Islas (William Morrow: $16.95; 224 pp.)</i>

There has been a lot of talk lately--by no means all of it foolish futuristic speculation or 1960s-style Chicano nationalist wish-fulfillment--about the birth of a new and original society along the United States-Mexican border.

To the people who live there, cities like San Diego and Tijuana, El Paso and Juarez, seem for better or worse to become more intertwined every year. As their economic and cultural interdependency grows, the international boundary shrinks into irrelevence--an increasingly hollow legal fiction in these binational metropolises that now resemble each other far more than they do the more fully American or Mexican cities farther north or farther south.

The region has an ethos of its own, and, by now, a name: Mex-America. In Carlos Fuentes’ marvelous dystopian novel, “Christopher Unborn,” set in an anarchic Mexico of the near future, this Mex-America has become an independent buffer state. The future, of course, is unknowable, but even the present is very radical indeed. As Arturo Islas’ new novel, “Migrant Souls,” ably demonstrates, Mex-America may not yet exist juridically, but it is already well entrenched as a state of mind.

It is not, by all appearances, a comfortable state to inhabit. “The truth is,” laments young Chicano lawyer Rudy Angel during one of the many family gatherings that punctuate Islas’ flawed, ambitious book, “we don’t know what we are because we don’t know who we are.” The answer, he decides, with a certain gritty rue, is that families like his own reside “on the border between a land that has forgotten us and another land that does not understand us.”

Islas understands this world of loss and mixed allegiance perfectly, and some of the strongest moments in his book occur when his characters wrestle with their inchoate, painful destinies.

“Migrant Souls” depicts the lives of several generations of the Angel clan in the border town of Del Sapo (both an anagram for Islas’ native El Paso), and, as the narrative unfolds, in other parts of the United States, particularly California. Although Islas has one of the Angels say that they are not immigrants but migrants--that is, that it is the border that is the alien construct and not their decision to move from one side of the Rio Grande to the other--his book provides a humane and sensible look at what it is to be a Mexican immigrant in the United States, particularly in his evocation of the younger Angels, professional people in cities such as Chicago and Washington.

As with the members of the family who have remained in Del Sapo, this generation also lives uncomfortably in two cultures and, if they at last have succeeded in belonging to either, it is only uncomfortably. When Rudy says, “Let’s keep the border and give both lands back to the Indians,” he is only half-joking.

To a certain extent, Islas has written a sort of “pre-history” of Mex-America. Unfortunately, his novel is far less successful as literature than it is as sociology or (implicitly) social criticism. There are moments when Islas’ considerable knowledge of the milieu of “Migrant Souls” seems to get in the way of his writing, as if, rather than give his characters a full measure of autonomy, he constantly feels the need to cram in one more accurate--but unnecessary--detail.

There is, of course, a generic problem with the kind of multigenerational saga that Islas has attempted. (“Migrant Souls” is the second volume of a projected trilogy about the Angel family). Inevitably, the author must try to shoehorn so much into the narrative that characterization in depth is elusive--probably the reason why most books of this type are very long. “Migrant Souls,” by contrast, is only 249 pages; yet it stretches from the 1940s to the present and includes several dozen characters. Even if Islas were the most brilliant stylist around, there is simply no space to do his characters justice. He isn’t, and he doesn’t.

Many of his descriptions are simply words, embodying little. Thus, one character marries “a decent man of Anglo-Mexican background.” Not only is background a windy simplification; decent, meant to do all the work in the sentence, is in fact all but meaningless. “Migrant Souls” is full of these sorts of complacencies of style. Characters never are astounded, they are “truly astounded”; they are “overwhelmed by fear and pity” or “filled with pity and gratitude”; they erupt into “whoops of laughter” and are forever “consoling” themselves, “gasping” or becoming “beside themselves.” Islas, so subtle when it comes to differentiating character, takes every shortcut where language is concerned. In fairness, it should be added that “Migrant Souls” has been praised by Denise Levertov and Adrienne Rich for both story and style, praise that I find incomprehensible; Islas is as wooden a writer as he is acute an observer.

It’s a pity, because Islas is concerned with subjects too rarely treated in contemporary American writing. We need a great realistic novel about the border. Had Islas written less self-indulgently, that book might have been “Migrant Souls.”