Cultures create institutions that reflect their values and interests. But it works both ways. Institutions create cultures, as well.

For example, the automobile industry was created by American ingenuity, entrepreneurship, hard work and enough natural resources to build millions of cars. At the same time, few inventions have done more to create modern America. The automobile has reinforced our distaste for practical mass transportation, as well as shaped the looks of our cities and towns. The automobile has even had a significant impact on the composition of the air that we breathe and our climate.

In fact, it's impossible to imagine modern America without the automobile.

Or without professional football. And America's relationship with the sport is similarly interesting and complicated.

America was a fitting location for the invention of football. All of the sports that we really like involve two teams trying to reach goals at opposite ends of fields or courts - baseball is the prominent exception. But football is the only one - except for its less-popular, non-American progenitor, rugby - that depends on violent force, only mildly restrained by rules, to reach its goal.

Other popular sports involve forays toward the goal in the opponents' territory, alternating with orderly, fluid retreats to defend one's own goal. Football is built around the principle of conquering and controlling territory - field position - in a way that progressively brings the goal into reach.

In short, football serves as an apt parable for the creation of our nation, which depended on the acquisition and control of territory by force. We're not the first nation to be created in this way, but this comparatively recent narrative is central to our history. I'm not saying that it was a bad thing. I'm just saying.

For decades football was a pleasant way to spend a crisp fall afternoon, but technology spawned the pervasive eminence of the modern game. Air travel allowed professional football's expansion to more cities, and the NFL appears to have its sights on international expansion.

Modern football and TV were made for each other, and broadcast technology has significantly enhanced the viewing experience. During the season, the amount of football available is remarkable. A devoted fan can watch games nearly any day of the week.

It would be difficult to overstate professional football's prominence in American life, and the modern game, a nearly $10 billion industry that shows no signs of slowing down, originally shaped by our culture, is now shaping our culture.

For example, consider the college game. In some respects, all football in America is now professional, and at last college players in some of the big schools are getting token monetary rewards for their skills, labor and the risks they take.

In another sense all football is driven by the professional game, as well. This insight comes courtesy of a massive offensive tackle who was in my freshman writing class at the University of Texas more than 30 years ago: "It doesn't matter how big or fast you are. Every guy out there thinks he's going to make it in the pros."

I suspect this sentiment reaches pretty far down into the high school ranks, as well. Thus the potential wealth and fame in the pro game nurture an unrealistic fantasy that affects the game at nearly all levels. And thus we're more willing to tolerate the football-related deaths of at least 19 young boys this past year, as well as engage in considerable denial about the physical damage that is an inevitable part of football.

Has pro football become too important? Admittedly, this is an easier question to ask when my traditional favorites - the Texas Longhorns and Dallas Cowboys - are suffering through lean years.

But maybe last week's revelation that the great New York Giants running back Frank Gifford suffered from chronic traumatic encephalopathy - along with nearly all NFL players who have been tested for the disease after their deaths - will remind us that occasionally we should ask when pro football stops being an entertaining passion and becomes an unhealthy obsession.