Now that the bitter election season is over, both parties will have to return to the explosive issue of illegal immigration.

Increased border patrol, a 700-mile fence to stop the easiest access routes (something President Bush signed into law two weeks ago), employer sanctions and encouragement of one official language can all help solve the crisis. But once the debate is renewed, congressional reformers will be blitzed by advocates of the failed status quo with a series of false assumptions concerning the issue.

Take, for example, the shared self-interest argument — that the benefits to both the U.S. and Mexico of leaving our borders open trumps the need for enforcement of existing laws and outweighs the costs to U.S. taxpayers that result from massive influxes of poor illegal immigrants.

Libertarian supporters of relatively open borders, for example, have long argued that illegal immigration is a safety valve for Mexico, one that prevents violent revolution south of our border. By allowing millions of poor people to cross illegally into the United States, we supposedly stabilize Mexico. Billions of dollars in remittances are sent back home to the needy left behind.

Yet for the last several weeks, the Mexican city of Oaxaca has been in near-open revolt. What started out as calls to remove the state governor, Ulises Ruiz, on charges of fraud and corruption has spiraled into a popular uprising of the type that's been seen in Venezuela and Bolivia.

Yet the state of Oaxaca is also one of the chief sources of illegal immigration to the United States. Hundreds of thousands of dissatisfied Oaxacans have fled to the U.S. and now send millions of dollars back southward. Why, then, is the city on the brink of chaos?

Could it be that far from stabilizing Mexico, the continual flight of millions of Mexico's disenchanted — one in 10 currently live in the U.S. — has only made things worse?

Young fathers and sons leave families torn apart and without immediate social support. The Mexican government puts off needed changes, assured that its most unhappy will leave for the U.S., and that their subsequent cash infusions will cover up state failures. Anger, corruption and cynicism, not market reform and stability, often follow. A corrupt Mexican government always survives, but its people each year fare worse — as we see now in Oaxaca.

Another canard about illegal immigration is that religious and family-oriented Mexican aliens are often corrupted by American popular culture, thus explaining why poverty, high-school dropout rates and arrests among Hispanics in the United States remain at high levels.

But as Heather MacDonald points out in the current issue of the urban-policy magazine City Journal, there is reason to believe that illegal immigrants did not develop these problems solely upon their arrival in the United States. Likewise, fewer students per capita graduate from high school in Mexico than they do here.

Finally, employers plead that without cheap foreign labor they would not be able to find enough American workers to maintain the surging American economy. But here, too, this seemingly logical supposition doesn't quite fit with reality.

Some U.S. counties with higher than average unemployment rates — such as California's Central Valley, where the unemployment rate often has been in the double digits — are a favored destination of illegal aliens. That suggests that there are already enough American laborers to meet job needs, but a fundamental failure to attract such manpower back into the workplace.

The ultimate — and more challenging — solution to a shortage of laborers may not be illegal immigration or even guest workers, but higher wages, a change in entitlement eligibility laws or a return to our own former positive attitudes about hard, physical work.

Areas in the United States that have experienced far less illegal immigration seem to have no insurmountable problems in manning restaurants, cutting lawns or serving the needs of hotel guests. Travel to the Midwest, for example, and you'll see that students are employed as cooks and maids. Construction relies on legal laborers.

The evidence suggests that massive illegal immigration causes as much upheaval inside Mexico as it supposedly prevents — while aggravating, not solving, problems in the United States.

What we need from this new Congress is not more hysteria about illegal immigration, but more re-examination of what seems true but really is not.

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