The Congress has received lots of free advice lately from Mexican government officials and illegal aliens waving Mexico's flag in mass demonstrations coast-to-coast. Most of it takes the form of bitter complaints about our actual or prospective treatment of immigrants from that country who have gotten into this one illegally -- or who aspire to do so.    

If you think these critics are mad about U.S. immigration policy now, imagine how upset they would be if we adopted an approach far more radical than the bill they rail against that was adopted last year by the House of Representatives -- namely, the way Mexico treats illegal aliens.    

In fact, as a just-published paper by the Center for Security Policy's J. Michael Waller, Mexico's Glass House, points out, under a constitution first adopted in 1917 and subsequently amended, Mexico deals harshly not only with illegal immigrants. It treats even legal immigrants, naturalized citizens and foreign investors in ways that would, by the standards of those who carp about U.S. immigration policy, have to be called "racist" and "xenophobic."    

For example, according to an official translation published by the Organization of American States, the Mexican constitution includes the following restrictions:

• Pursuant to Article 33, "Foreigners may not in any way participate in the political affairs of the country." This ban applies, among other things, to participation in demonstrations and the expression of opinions in public about domestic politics like those much in evidence in Los Angeles, New York and elsewhere in recent days.
  

• Equal employment rights are denied to immigrants, even legal ones. Article 32: "Mexicans shall have priority over foreigners under equality of circumstances for all classes of concessions and for all employment, positions or commissions of the Government in which the status of citizenship is not indispensable."
  

• Jobs for which Mexican citizenship is considered "indispensable" include, pursuant to Article 32, bans on foreigners, immigrants and even naturalized citizens of Mexico serving as military officers, Mexican-flagged ship and airline crew, and chiefs of seaports and airports.
  

• Article 55 denies immigrants the right to become federal lawmakers. A Mexican congressman or senator must be "a Mexican citizen by birth." Article 91 further stipulates that immigrants may never aspire to become cabinet officers, as they are required to be Mexican by birth. Article 95 says the same about Supreme Court justices.  In accordance with Article 130, immigrants -- even legal ones -- may not become members of the clergy, either.
  

• Foreigners, to say nothing of illegal immigrants, are denied fundamental property rights. For example, Article 27 states, "Only Mexicans by birth or naturalization and Mexican companies have the right to acquire ownership of lands, waters and their appurtenances, or to obtain concessions for the exploitation of mines or of waters."
  

• Article 11 guarantees federal protection against "undesirable aliens resident in the country." What is more, private individuals are authorized to make citizen's arrests. Article 16 states, "In cases of flagrante delicto, any person may arrest the offender and his accomplices, turning them over without delay to the nearest authorities." In other words, Mexico grants its citizens the right to arrest illegal aliens and hand them over to police for prosecution. Imagine the Minutemen exercising such a right.
  

• The Mexican constitution states that foreigners -- not just illegal immigrants -- may be expelled for any reason and without due process. According to Article 33, "the Federal Executive shall have the exclusive power to compel any foreigner whose remaining he may deem inexpedient to abandon the national territory immediately and without the necessity of previous legal action."
  

As the immigration debate in the Senate moves into a decisive phase this week, legislators who believe America's southern border must be secured, the nation's existing immigration laws enforced and illegal aliens not rewarded with permanent residency and a direct path to citizenship are being sharply criticized and, in some cases, defamed as bigots and xenophobes.

Yet, even Senators' maximalist positions generally pale in comparison with the treatment authorized by the Mexican constitution.    

So the next time such legislators -- and the majority of Americans for whom they speak -- are assaulted by Mexican officials, undocumented aliens waving Mexican flags in mass demonstrations here in the United States, clergy and self-described humanitarians, businessmen and other advocates of illegal immigration, ask them this:

Would they favor having the U.S. impose the same restrictions on immigrants -- legal and illegal -- that Mexico imposes on their counterparts there?    

Nothing of the kind is in the cards, of course. Nor should it be. Legal immigration and the opportunity for foreign investors and other nationals to contribute to this country are not only one of its hallmarks -- they are among the reasons for its greatness.    

Still, we should not allow the hypocrisy of others' treatment of undocumented aliens in their countries to induce us to refrain from taking effective steps to prevent further illegal immigration.

These steps must be:

Building a fence along our southern border.

Enforcing immigration laws in the workplace and elsewhere.

Discouraging more such violations -- with potentially grave national security implications -- by dealing effectively with those who have already broken those laws by coming here without permission.
    
Frank J. Gaffney, Jr. is the president of the Center for Security Policy in Washington, D.C.