In the dark of these rural spring mornings, I see full vans of Mexican laborers speeding by my farmhouse on their way to the western side of California's San Joaquin Valley to do the backbreaking work of weeding cotton, thinning tree fruit and picking strawberries.

In the other direction, even earlier-morning crews drive into town — industrious roofers, cement layers and framers heading to a nearby new housing tract. While most of us are still asleep, thousands of these hardworking young men and women in the American Southwest rise with the sun to provide the sort of unmatched labor at the sort of wages that their eager employers insist they cannot find among citizens.

But just when one thinks that illegal immigration is an efficient win-win way of providing excellent workers to needy businesses, there are also daily warnings that there is something terribly wrong with a system predicated on a cynical violation of the law.

Three days ago, as I watched the daily early-morning caravan go by, I heard a horrendous explosion. Not far my home, one of these vans had crossed the white line down the middle of the road and hit a pickup truck head-on. Perhaps the van had blown a bald tire. Perhaps the driver was intoxicated. Or perhaps he had no experience driving an overloaded minivan at high speed in the dark of early morning.

We will probably never know — since the driver ran away from the carnage of the accident. That often happens when an illegal immigrant who survives an accident has no insurance or driver's license. But he did leave in his wake his three dead passengers. Eight more people were injured. Both cars were totaled. Traffic was rerouted around the wreckage for hours.

Ambulances, fire trucks and patrol cars lined the nearby intersection. That accident alone must have imparted untold suffering for dozens of family members, as well as cost the state thousands of dollars.

Such mayhem is no longer an uncommon occurrence here. I have had four cars slam into our roadside property, with the drivers running off, leaving behind damaged vines and trees, and wrecked cars with phony licenses and no record of insurance. I have been broadsided by an undocumented driver, who ran a stop sign and then tried to run from our collision.

These are the inevitable but usually unmentioned symptoms of illegal immigration. After all, the unexpected can often happen when tens of thousands of young males from Mexico arrive in a strange country, mostly alone, without English or legality — an estimated 60 percent of them without a high school degree and most obligated to send nearly half of their hard-won checks back to kin in Mexico.

Many Americans — perhaps out of understandable and well-meant empathy for the dispossessed who toil so hard for so little — support this present open system of non-borders. But I find nothing liberal about it.

Zealots may chant ÁSi, se puede! all they want. And the libertarian right may dress up the need for cheap labor as a desire to remain globally competitive. But neither can disguise a cynicism about illegal immigration, one that serves to prop up a venal Mexican government, undercut the wages of our own poor and create a new apartheid of millions of aliens in our shadows.

We have the entered a new world of immigration without precedent. This current crisis is unlike the great waves of 19th-century immigration that brought thousands of Irish, Eastern Europeans and Asians to the United States. Most immigrants in the past came legally. Few could return easily across an ocean to home. Arrivals from, say, Ireland or China could not embrace the myth that our borders had crossed them rather than vice versa.

Today, almost a third of all foreign-born persons in the United States are here illegally, making up 3 percent to 4 percent of the American population. It is estimated that the U.S. is home to 11 million or 12 million illegal immigrants, whose constantly refreshed numbers ensure there is always a perpetual class of unassimilated recent illegal arrivals. Indeed, almost one-tenth of Mexico's population currently lives here illegally.

But the real problem is that we, the hosts, are also different from our predecessors. Today we ask too little of too many of our immigrants. We apparently don't care whether they come legally or learn English — or how they fare when they're not at work. Nor do we ask all of them to accept the brutal bargain of an American melting pot that rapidly absorbs the culture of an immigrant in exchange for the benefits of citizenship.

Instead, we are happy enough that most labor vans of hardworking helots stay on the road in the early-morning hours, out of sight and out of mind. Sometimes, though, they tragically do not.

Victor Davis Hanson is a classicist and historian at the Hoover Institution, Stanford University. Reach him at author@victor hanson.com.