We are on the receiving end of an economic diaspora out of Mexico. The only way to stop Mexican citizens from swarming across our borders is to attack the root cause of the calamity. Since the source of the disaster is the Mexican political system, which fails to provide jobs or social services for its citizens, the only way to solve the problem is by using the Bush Doctrine of Preemptive War.

That’s right. The only way we can stop work-starved Mexicans from coming to the United States is to invade Mexico, take over the government and fix the Mexican economic and political system so that it takes responsibility for its citizens who have no resources or prospects.

Mexican society today looks much like American society will look in 20 years if the Republicans stay in power: The country is run by a tiny, corrupt, uber-wealthy class of elites who allow the appearance of democracy to play out to appease the meager, mostly urban middle class. Meanwhile, millions of Mexican citizens live in the kind of poverty I remember around the Cherokee Indian Reservation in the Appalachians in the 1960s.

To be clear, I’m not advocating preemptive war with Mexico; I’m saying it is the only way we can stop the immigration. I oppose the Bush Doctrine, which as applied to the invasion of Iraq has led to what has to be the worst foreign policy blunder in U.S. history.

But all the other solutions on the table range from draconian to pie in the sky:

Build walls: The silliest idea is that we should build a wall along the 2,000-plus mile Mexican border. This is the “Star Wars” of immigration hysteria. Not only would this cost millions of dollars to build and years to complete, it wouldn’t work. People would just go around it and come in by sea.

Round ‘em up: There are an estimated 12 million undocumented residents here. Rounding them up would also cost millions of dollars and take forever. Since most would leave family here, the recidivism rate would probably be higher than 50 percent.

Stop services: We tried this in California in 1994 and it was found to be unconstitutional. On a practical level, if we refuse healthcare and education to undocumented residents, our cities would soon be awash in sick and infectious children. (Imagine how this would exacerbate an ebola virus or bird flu outbreak.) And when the children grow up, what would we do with all those uneducated adults?

What is the solution then? We should accept the fact that they are coming here and work the system around that fact. We can do that by decriminalizing worker immigration from Mexico and:

• Insist that each Mexican citizen have a Mexican government photo id card when they come to the U.S.
• Insist that Mexico keep track of its citizens abroad
• Issue work visas to Mexican citizens who have jobs here, just as Mexico issues visas to Americans who work there
• Mexicans who drive across the border must have Mexican drivers licenses and U.S. car insurance, just as U.S. drivers must have valid drivers licenses and must take out Mexican car insurance when we drive into their country
• Set up a fund that non-resident workers pay into instead of Social Security that contributes to the cost of healthcare and education provided to non-residents
• Bill the Mexican government for costs to care for and educate its citizens in the U.S.
• Encourage Mexicans to learn English, just like Americans who reside in Mexico must learn Spanish, including teaching in English only

When the potato famine swept across Europe in the 1840s, millions of people found themselves starving in their homes. Just about everyone who had the means to travel fled the continent — and especially Ireland and the British Isles — for America.

The Irish, in particular, were not welcomed here. But they were desperate, and felt relatively lucky to take the most menial jobs — the jobs Americans at the time did not want.

I don’t think anyone in retrospect would say that Irish immigration of the 19th Century netted to the negative for the United States of today.

The main difference between the Irish immigrants of 1846 and the Mexican immigrants of 2006 is that we have laws in place that ostensibly prevent them from coming here. And, oh yeah, the color of their skin.

Unless and until the Mexican government can take care of its own, Mexican immigrants are here to stay — and more are on the way.

We can either accept this reality and deal with it, or keep tossing this political football around for another 20 years. (My bet is on the latter.)