MEXICO'S Constitution guarantees citizens the right to free movement throughout the republic, and some here suspect that somewhere in the Mexican subconscious that right is taken to extend to all the lands Mexico lost to the United States - including California - in the last century.
Thus it is received here as a particular affront, and is cause for extraordinarily sharp rhetoric, when California voters appear on the verge of approving an anti-immigrant proposition to deny education and other social services to illegal aliens, or when San Diego County officials vote, as they did last week, to declare a state of emergency over the daily arrival of illegal immigrants - most from Mexico.
Mexico's irritation at California's ``SOS'' (Save Our State) referendum had been lightly veiled until last week, when word of San Diego County's declaration prompted officials and editorialists to pull out the stops. California, and the US in general, were said to be turning increasingly ``xenophobic'' and ``racist.''
The Foreign Relations Secretariat, which had earlier criticized the SOS referendum, released a statement calling the declaration ``an attack on the spirit of cooperation'' that should reign between the US and Mexico. It also said the anti-immigrant climate threatened economic and trade relations between Mexico and California.
US Ambassador to Mexico James R. Jones acted quickly to distance the federal government from California's actions. He advised Mexican officials that the White House would not entertain San Diego's request for emergency federal assistance and assured journalists that the US government is ``absolutely ... not racist.''
Mexican President Carlos Salinas de Gortari, in New York for the United Nations General Assembly opening, will have the chance to gauge the US position when he meets today with President Clinton. Mexican officials say the recent events in California, of keen interest to Mexico, will figure specifically on his agenda. Of particular concern is the guarantee of respect for the ``human rights'' of Mexicans on US soil, they add.
Mexicans sense that much of the anti-immigrant tempest in California is directed at them. Objectively, they agree that the US has the right, and even responsibility, to develop immigration policy. But at another, more subjective level, the conviction shows through that migration to San Diego, or Los Angeles, or Colorado, or San Antonio is an atavism no less natural than is migration from the Mexican states of Oaxaca or Michoacan to Mexico City.
Braving observations that Mexico would be the first to cry ``violation of sovereignty'' and ``unappreciated outside intervention'' if the tables were turned, Mexican officials have not shied from attacking the run of anti-immigrant measures in the US.
``We cannot stand by with our arms folded before the growing hysteria that seeks to blame Mexicans for all the social and economic ills affecting American society,'' said Andres Rozental, deputy foreign minister, earlier this month. That was before San Diego County's declaration.
Last week Mr. Rozental called the SOS initiative ``unfortunate, absurd, and stupid,'' while the Foreign Relations Secretariat reiterated its concern that Mexicans are becoming the scapegoats for ``the problems of US society....''
The fact that the latest anti-immigrant surge is taking place in part of what used to be Mexico only adds insult to the injury. That territorial loss remains an under-the-surface wound, that even the president acknowledges is part of the Mexican psyche.
At a Latin American summit earlier this month in Rio de Janeiro, Mr. Salinas cited the trauma of that loss to explain Mexico's opposition to any US military intervention in Haiti. ``Having suffered an external intervention by the US, in which we lost more than half of our territory,'' he said, ``Mexico cannot accept any proposal for intervention in any nation of the region.''
When Mexicans migrate to California, something inside tells them it is just another part of home.