THERE IS AN OBLIGATORY SCENE in every movie about the border between Texas and Mexico: A man draws a line in the dirt with his boot. The line means something different in each movie, and yet, there it is, a narrow little rut in the ground that the characters gesture toward, talk about, and ponder before they stand meaningfully on one side or the other. In Viva Max! (1969) Peter Ustinov, in the role of a Mexican general who has recaptured the Alamo in modern times, draws a line in front of his troops in the Alamo dirt just as Travis in legend drew the mother of all lines during the real siege. In The Border (1982) Jack Nicholson, playing a Border Patrol agent who is slowly turning corrupt, draws the line between himself and an already corrupt agent played by Harvey Keitel. Nicholson shouts excitedly that he might do some bad things but he won’t be involved in murder—that’s a line he won’t cross. In Lone Star, which opened in early July and features our cover subject, Matthew McConaughey, the line is drawn by “Chucho,” who owns a tire repair shop in a Mexican border town. After dragging his boot through the rocky soil, he says to the sheriff from the town on the Texas side, “Bird flying south—you think he sees that line? Rattlesnake, javelina—whatever you got—halfway across that line they don’t start thinking different. So why should a man?”

Just why men might start thinking differently when they cross the border is a good question, but there’s no question that they do, rattlesnakes and javelinas notwithstanding. Historians have written many pages about the events and the natural and historical forces that created Texas. There was the colonization, the revolution, the cotton kingdom, the cattle kingdom, the oil kingdom, and now perhaps the technology kingdom. But, as each day passes, it appears more and more clear that the border has been and still is the most powerful defining force on Texas. Even the revolution, honored as a fight for freedom, can just as easily and correctly be described as a fight to move the border of Mexico from the Red River south to the Rio Grande. There, Spanish culture and English culture wafted back and forth across the river, as unstoppable as the wind, and made Texas a blend of both, unique in all the world. Yet by creating the border and sanctifying it by law and by treaty, the two cultures recognize that, mix though they might, they each want to maintain the dignity of a separate identity. It could be that there was a time in our remote past when the two sides of the Rio Grande were indistinguishable, and that would have been a time when Chucho’s moody philosophizing would have had a point. Today, it is impossible to cross the border in either direction without being struck immediately by how different, despite their many similarities, the two sides really are. As the sheriff answers Chucho, “Your government’s always been pretty happy to have that line. The question’s just been where to draw it.”

With two great cultures grinding against one another and with the dramatic sparks that grinding produces, the border has inspired fewer imaginative works on this side than it ought to have. It is present in books and movies, but usually only as a line characters cross seeking safety or adventure or riches or whatever and not present as an idea, as a theme to be explored. Cormac McCarthy’s novels are an exception, but it’s hard to think of other major works that are. Among movies, there are many in which characters go back and forth from Texas to Mexico, but only the three mentioned above bother with the border itself.

The Border is the worst of the three. Despite its title, a theme song beautifully sung by Freddy Fender, and a fine performance by Nicholson, the movie is simply a pretentious thriller about smuggling illegal workers through the desert near El Paso. It has no ideas about the border and nothing but the most superficial feelings for either Texas or Mexico. Viva Max! is a different matter. It does not pretend to be anything other than the light spoof it was intended to be. Part of its interest is that it is a movie no one would make today. The laziness and incompetence of the Mexican soldiers Ustinov brings with him across the river to retake the Alamo would surely be viciously attacked as racial stereotyping, never mind that the Anglo police chief and Army officers are just as bumbling as they flail around trying to roust the Mexicans out of the old mission. I take it all as meaning to gently satirize both cultures, which it does entertainingly enough. Viva Max! is also mildly subversive. Where else can you see a Mexican general on a white horse at the head of his troops parade before cheering crowds through downtown San Antonio? The spectacle seems fitting after all these years, for there would never have been an Alamo if not for Santa Anna.

That leaves Lone Star, written and directed by John Sayles, whose other movies include Brother From Another Planet, City of Hope, and Eight Men Out. Though made on a small budget, it’s a good movie that plunges right into the world of the border to find out what’s going on and actually figures out an answer. That alone should earn it a place in the pantheon of important works about Texas, although it’s marred by its faults, starting with its name. Lone Star is the kind of obvious title television executives give to overblown and uninspired miniseries. Worse, the words “Lone Star” are associated most closely with the era of the republic and its Lone Star flag and with the great Western ranching frontier. The border is the one place in Texas where those associations are at their faintest.

But the title does do one thing right. It announces that this is a movie about Texas and that Sayles is not shrinking from comparison with the defining Texas movies of the past, movies like Giant, Hud, and The Last Picture Show. He doesn’t benefit in every way from the comparison because Hollywood talent and budgets, when used well, produce movies whose technical craftsmanship is wonderful to see. Next to them, Lone Star looks almost dog-eared. Nevertheless, it holds its own for the simple reason that it is about the border, as none of the other movies are, and it says what none of the other movies say—that the border made Texas.

For Sayles, our border is primarily a place where races meet and consequently, although secondarily, a place where cultures meet. While he’s right about that, his concentration on race and then on culture to the exclusion of all else makes his picture of the border recognizable but incomplete. There is, for instance, slight mention of drugs in the movie, which is practically a fatal omission, since drug lords manipulate power and law enforcement on both sides of the border, and drug money supercharges the economy. Since the main character is the sheriff of a border county, one would presume that drugs, drug busts, drug dealers, drug seizures, drug money, and drug users would come up at least once during his day’s work, but except for a passing reference to marijuana, they don’t.

Nor is there any sense of the single most important activity along the border—commerce, including but hardly limited to commerce in drugs. Except for the tiny and remote ones, border towns exist in a frenzy of buying and selling, carting and hauling, loading and off-loading at all hours of the day and night. In Lone Star the only economic activity seems to be preparing and serving Mexican food. Nor is there anything of importance about religion in the movie, no praying or lighting of candles, no Virgin of Guadalupe, no churches, or any of the other practices and icons of Mexican Catholicism. It’s a huge omission. But there is in the movie an elaborate subplot involving blacks on a military base in the county. There are military bases near the border, and there are black soldiers on them, and there are blacks in small numbers living in border towns. But black people, black issues, and black culture are more a footnote in the area than an important presence.

So Lone Star is far from perfect, but it does show very well power shifting beneath the feet of Anglos and Mexican Americans. There are arguments about what to teach in Texas history classes, arguments about whom to back in political races, arguments about whether to speak English or Spanish, arguments about letting government contracts and whom should be honored with public monuments. Everywhere people are choosing sides based on their ethnicity. The Anglos feel outnumbered; the Mexicans feel outmaneuvered and unfairly overpowered. With all this swirling around, the Anglo sheriff, not too long divorced after a bad first marriage, and a widowed Latin schoolteacher rekindle their high school romance, which back then both their families had forbidden. (I am about to reveal an important point in the plot. It’s not hard to guess as you watch the film, so I don’t think knowing it would spoil the movie for anyone. But if you intend to see the movie, you might stop reading here.) They cannot resist the pull between them. Even through the years with other people, they always felt they should be together. They decide to get married. Then the sheriff discovers that they have the same father; they are half brother and half sister. She says she can’t have children anymore—don’t they love each other and want to stay together anyway? They agree that they do. She speaks the last lines of the film: “Everything that went before, all that stuff, that history—the hell with it, right? Forget the Alamo.”

The importance of a line drawn in the sand, and the importance of a border, is that you must choose to stand on one side or the other and then live with the decision. The two lovers make such a decision. The result is a willing, intense, difficult but happy, and incestuous marriage in defiance of all convention. It’s one thing to say that Texas is a marriage of two cultures. It’s another to say that Texas is a marriage like this one. The power of Lone Star is that it makes you ask yourself, “Is that really what we are?”