In 2005 the Border Patrol stopped 1.19 million people trying to enter the United States illegally; 98.5 percent of them at the Mexican border

Robert J. Samuelson:

Of those who got through and stayed (crude estimate: some 500,000 annually), about two-thirds lack a high school education. Even a country as accepting of newcomers as the United States cannot effortlessly absorb infinite numbers of poor and unskilled workers. Legal immigration totals 750,000 to 1 million people annually, many of them also unskilled.

I do not like advocating a fence. It looks and feels bad. It's easily stigmatized as racist. It would antagonize Mexico. The imagery is appalling, but it beats the alternative: a growing underclass and social tensions. Moreover, a genuine fence would probably work. The construction of about 10 miles of steel and concrete barriers up to 15 feet high in San Diego has reduced illegal crossings in that sector by about 95 percent since 1992, reports Rep. Duncan Hunter (R-Calif.), a supporter of a U.S.-Mexico fence. Sure, there will be tunnels and ladders. But getting in will be harder. Policing will be easier.

We also need to stiffen employer fines for hiring illegal immigrants. Businesses should have to check prospective workers against computer databases with Social Security numbers, passports or immigration documents. Now employers only have to inspect physical documents, which are easily forged. Even these lax rules are widely flouted and poorly policed. In 2004 the Department of Homeland Security cited only three employers for possible violations, says the Government Accountability Office. With an estimated 10 million to 12 million illegal immigrants in the United States, that's mighty slim.

Fewer jobs and genuine border control ought to curb illegal immigration. Good. Naturally, there's another point of view. It is that the United States needs more unskilled workers to fill jobs native-born Americans won't take. One solution is to admit more unskilled workers legally. By this view, Hispanics are assimilating economically and culturally as fast as some groups in the past.

Perhaps. But common sense and available evidence suggest skepticism. If there are "shortages" of unskilled American workers, the obvious remedy is to raise their wages. A Texas roofing contractor testified to Congress that he couldn't get enough roofers at $9 an hour. Okay, increase it to $10 or $12. Higher wages will bring forth more workers. Perish the thought. Business groups, led by the U.S. Chamber of Commerce, clamor for more guest workers. That's a euphemism for cheap labor. These business groups seem unperturbed by extravagant increases in chief executives' pay. But they're horrified by anything that might raise the wages of maids, waitresses, laborers or gardeners.

As for assimilation, it's true that millions of Hispanic families are moving into -- and reshaping -- the American mainstream. But average trends look less encouraging. Since 1990 about 90 percent of the increase in people living below the government's poverty lines has come among Hispanics. That has to be mainly immigrants and their U.S.-born children. In a report, the Pew Hispanic Center notes:

Residential segregation is increasing. In 2000, 43 percent of Hispanics lived in neighborhoods with Hispanic majorities, up from 39 percent in 1990.

The median net worth of Hispanic households is about 9 percent of that of non-Hispanic whites (net worth is what people own minus what they owe).

Only about a quarter of Hispanic college students graduate compared with about half for non-Hispanic whites.

Assimilation takes time. The big difference between today's Hispanic inflows and past immigration waves is that those stopped. History or restrictive laws intervened. There was time for newcomers to adapt. Left alone, there's no obvious reason why the present Hispanic immigration should even pause. Today's unskilled arrivals make it harder for yesterday's to get ahead. The two compete. In 2004 the already-low median wages for foreign-born Hispanics dropped 1.6 percent, reports Rakesh Kochhar of the Pew Center.

There's a paradox. To make immigration succeed, we need to curb some immigration. That's why it's vital to control our border. It also explains why it's important not to "solve" that problem merely by legalizing these huge inflows. Unfortunately, the legislation being considered by the Senate Judiciary Committee would do precisely that. Among other things, it would create a virtually open-ended guest worker program.

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