We are very proud of the recent discoveries of oil and natural gas in Mexico. --Jimmy Carter, Washington, D.C., Feb. 13, 1979

I cannot imagine a more appropriate day for our own reunion and to express the feelings that the people of my country have towards yours.   --Jimmy Carter, Mexico City, Valentine's Day, 1979

ON FEBRUARY 13, Jimmy Carter was Mexico's boasting father; on Valentine's Day, he was its kneeling suitor. The supplicant posture of the latter is a harbinger of the recent change in U.S.-Mexican relations; the untrammeled paternalism of the former is now an outdated extreme.

Before Mexico struck oil, the United States could play the role of parent--an inexcusably selfish, and often negligent parent, but a parent nonetheless. The disguise, however, was too transparent and too often cast aside to conceal the raw facts of America's superior might and Mexico's dependence on the U.S. as a market for 70 per cent of its exports and as a source of foreign investment.

By a curious twist of fate, which some might call poetic justice, Mexico finally has something that the United States desperately wants--huge reserves of oil and natural gas--and has no intention of obediently giving it away. Experts predict that by 1980 Mexico will be the world's fifth largest producer of oil, just behind Saudi Arabia.

The United States anachronistic attempts to force its will on Mexico arbitrarily have backfired. Since President Lopez Portillo's visit to Washington D.C. in early 1977, relations between the U.S. and Mexico have progressively deteriorated. When Carter vetoed a privately negotiated agreement to buy Mexican oil at $2.60 a barrel, Mexico proudly announced that its oil was not for sale at a lower price, rerouted pipelines originally bound for the U.S., and signed contracts with France and Canada. When the Immigration and Naturalization Service (INS) announced its plans to build a fence between Juarez and El Paso, which a spokesman for the construction firm said would have edges sharp enough to cut off the toes of any Mexican who tried to cross it, the Mexican government was willing "to fight to the last barb to tear the thing down," one American living in Mexico said. When the U.S. trade restrictions on Mexican goods oscillated unpredictably, Lopez Portillo voiced his outrage.

While the calumnies heaped on the American government by Mexican leadership have become almost an annual ritual, the United States has only recently begun to take the Mexican charges seriously. American harshness toward Mexico in public actually masks division within the Carter ad-powerful Mexico, whose threats now have a more ominous ring than they did five short years ago.

For instance, while Energy Secretary James Schlesinger has consistently opposed giving Mexico any special treatment on trade or immigration policy (he was in back of Carter's rejection of the oil purchase), the President's National Security Council issued Presidential Review Memorandum (PRM) 41 in mid-December, which recommends granting Mexico concessions on certain issues in hopes of gaining access to "the most promising new source" of oil for the 1980s.

THE MOST RECENT proof of the incoherence of administration policy towards Mexico took place this Valentine's Day. At the opening ceremonies in Mexico City, when Carter remarked that he could not "imagine a more appropriate day" for Mexico and the United States to meet, he could not have realized the irony of his comment. For as he extended his hand, the Commerce Department, unknown to the President, turned what was proferred as a handshake into a slap in the face--on the same day, the Commerce Department announced its unilateral decision to close a big export promotion center in Mexico, making a mockery of Carter's trip, which was supposed to open up lines of communication between the two nations on the very question of improving trade relations.

In all likelihood, the United States's overriding need for Mexico's oil and gas will force the U.S. to adopt a more consistent and compromising attitude on the price it will pay for Mexico's resources. And it may even motivate the United States to develop a saner, more sophisticated and more humane approach to other Mexico-related issues.

Already there are some signs that the United States will liberalize its immigration policy. The proposed erection of a six-and-a-half-mile-long fence at El Paso, which would only have diverted immigrants to the other 1993 miles of unfenced border, was more an instance of window-dressing than of a sincere attempt to slow unlawful migration of impoverished Mexicans. INS Commissioner Leonel Castillo, whose grandparents were Mexican immigrants, has instituted policies more sympathetic to the plight of the immigrant. Not only has he reduced to half the personnel working to seize Mexicans living illegally in the United States, he has also upgraded the detention centers where illegal immigrants are housed before being shipped back to Mexico. Carter, too, may be softening his stance; while he advocated an increased number of border guards in 1977, he has slashed funding for 254 guards in his 1980 budget proposal.

IF THE U.S. honestly wants to slow Mexican immigration, it will need to cooperate with Mexico to help it improve its internal economic conditions. As of now, a quarter of the Mexican work force is unemployed, and another quarter doesn't make enough to live decently. And as long as this situation worsens, Mexicans will continue to cross the border in ever increasing numbers, lured by jobs and higher wages.

The U.S. can help Mexico create jobs for its citizens in a number of ways. It could, for example, relax trade restrictions on goods with high labor costs. It could also give direct financial support to Mexican-run programs like PIDER, which has been phenomenally successful in creating jobs and improving living conditions in the poorest rural areas, which are the main source of illegal immigrants.

Not unexpectedly, the Valentine's Day meeting between the two Presidents did not produce much in the way of concrete agreements. Neither of them could afford to give too much in the face of nationalistic sentiments in each of their nations. However, they did separate on friendly terms, having agreed to talk some more. Mexico's discovery of oil may have healthy consequences in more than the obvious ways. Not only will it forestall the day when the world runs out of gas, but it may also force the United States to grow up and stop treating its southern neighbor like a child.