The issue of illegal immigration blows hot and cold in American politics. Right now, the issue is hot.

Various proposals have caused a congressional deadlock. Some, particularly in the House, are pushing for a wall extending along the Mexican border and other tough enforcement measures. Others, particularly in the Senate, want some form of amnesty (under a different name) with more enforcement of the approach adopted in the mid-1980s: control at the level of business hiring and employment. Let’s call these two opposing positions Plan A and Plan B.

Opponents of Plan A inevitably say that walls are not effective. But that depends on the kind of wall. The Berlin Wall was very effective; very few got across even though those that tried knew they would be welcomed on the other side. The Maginot line on the French-German border forced the Germans in World War II to invade France through Belgium. Economy-minded French politicians didn’t want to spend the money to extend the line along the Belgian border. And that is just the point. Walls of the Berlin/Maginot type would cost billions to construct and police. Congress is not going to spend that much; any compromise is likely to be an ineffective chain-link fence and a symbolic increase in border guards. Just as the Germans went around the Maginot line, so, too, will illegals go around, through, or under whatever fence is likely to be constructed under Plan A.

Plan B is essentially a repeat of what was tried in the 1980s. It has a fatal flaw. Businesses can be asked to look at documents such as birth certificates and green cards before hiring. But counterfeits of such documents can easily be printed; false papers are readily available. In the end, we were unwilling to hold businesses accountable for determining which documents are genuine. Nor were we willing to produce a difficult-to-fake national ID card. The issues go beyond civil liberties concerns, which are real enough. A truly difficult-to-counterfeit card, presumably some kind of electronic card with personal information embedded in it, would cost billions to manufacture, distribute, and administer.

At any point in time, there are about 150 million people in the U.S. labor force. Another 7 or 8 million work or look for work at some time during the year. We would have to deliver cards to all of these people, carefully verifying they were who they said they were. If we mistakenly gave cards to illegals based on phony papers, it would be the ultimate amnesty program. Manufacturing the cards and verifying the identities of everyone who needed or wanted one would be a huge undertaking, a Maginot line of card production and distribution. It won’t happen.

So is there a Plan C, one that doesn’t give the business community the task of enforcing immigration laws and that won’t cost vast sums and raise civil liberties concerns? Opponents say illegal immigration depresses wages, particularly at the low end of the labor market. So let’s raise the minimum wage federal and state to a level that would be consistent with whatever legal immigration we would like to see. Then let’s enforce that wage and collateral labor standards such as provision of workers’ comp, adherence to workplace safety standards, etc.

Would this policy reduce the number of jobs available? Presumably, it would but that is what opponents of illegal immigration want. Hamburger flipping, car washing, hotel bed making, apparel production, and strawberry picking would cost more, absent the illegals. There would be fewer such jobs and with fewer jobs on offer, the attraction to enter the U.S. illegally would diminish. In California at least, both the Democratic Legislature and the Republican governor are pushing for a minimum wage increase, although they can’t agree on the details.

Is Plan C perfect? No. But we are not going to adopt either Plan A or B in a meaningful way; the costs are too great. So it’s either Plan C or we can just leave the issue alone.

Daniel J.B. Mitchell is the Ho-su Wu Professor at the Anderson School of Management and School of Public Affairs at UCLA.