No presidential sashes -- yet -- on Mexico's military men

In the wake of Mexico's financial emergency, rumors have swept this city that the military will seize power, just as it has done in 11 other Latin American countries.

A prime reason for President Jose Lopez Portillo's nationalization of private banks was to marshal patriotic fervor against pin-striped-suited scapegoats in an unprecedented time of troubles.

Yet, Mexico's tottering economy aside, the prospect of military intervention is minimal to nil. Such interference usually takes place in the absence of countervailing civilian power; that is, where the judiciary, congress, presidency, political parties, trade unions, and other institutions are ineffective. Mexico's courts are weak, and the congress - though enlivened by 101 opposition members - resembles a rubber stamp. Yet, the ruling PRI is a formidable party, thanks in large measure to the 3.5 million union members who compose its labor sector.

But at the apex of civil authority stands the president - as chief of state, head of the government, leader of the PRI, and commander-in-chief of the armed forces. Should protection be required, he can summon the crack 5,000-man Presidential Guard, a combination of palace sentinel and secret service which operates under direct orders of the president, not the defense minister.

The escalation of the current crisis has found the defense minister, Gen. Felix Galvan Lopez next to the lame duck president at public ceremonies to emphasize his organization's loyalty to the system. The general's counterpart, Navy Minister Ricardo Chazaro Lara, has been equally supportive.

Developments in the last decade have served to crystallize the mission of Mexico's military. The first priority of protecting its frontiers always seemed more rhetorical than real: It could never defend itself against the US in the unlikely event of a conflict; and Tennessee-sized Guatemala poses little threat to this Spanish-speaking ''colossus of the North.''

Thus the army has concentrated on internal security. Shooting down hundreds of demonstrators at the Plaza of the Three Cultures in October 1968; extirpating Lucio Cabanas's Guerrero-based rural guerrillas in the early 1970s; and cowing, if not wiping out, the urban-focused 23rd of September Communist League. Army units, acting under orders from local authorities, have also ousted and killed peasants occupying the lands of affluent farmers. Disaster relief forms a less dramatic part of domestic military functions.

Now Mideast-sized oil fields complemented by the designation of a 200-mile economic zone for mineral and marine resources have invested the armed forces with a new raison d'etre. Galvan Lopez linked oil to national defense when he referred to black gold as a ''magnet that attracts men and people. It is an inexhaustible source of envy, friction, and war,'' he said. Moreover, a ''drop of oil is worth a drop of blood,'' he added.

Nationalism and anticommunism suffuse Mexico's armed forces, and no ideologically dissident clique of captains and majors has sprung up to challenge the military and political elite. Though modestly paid, younger officers take pride in the enhanced professionali-zation of their services. For instance, the ultramodern Heroico Colegio Militar which opened in 1976 as Mexico's West Point, represents a $200 million symbol of civilian tribute to the army's fidelity.

Improvements in the rigorous curriculum of the Superior War College, a choice assignment for upwardly mobile middle-grade officers, have conferred even greater distinction on its diploma. And a National Defense College offers classes in force development, communications, international studies, and other subjects to a small, select group of colonels and brigadier generals.

While its slice of the national budget remains among the lowest in Latin American (2.3 percent), Mexico's military saw its appropriations shoot up 54 percent last year. Traditionally, the armed forces have relied on World War II vintage tanks, aircraft, and artillery pieces. But petroleum revenues are facilitating access to the most sophisticated hardware in the Caribbean basin, with the exceptions of Cuba and Venezuela.

The new weapons, including a dozen F-5 jet fighters, the issuance of G-3 automatic rifles to units, and the replacement of horses with tanks and personnel carriers in most of the cavalry, will scarcely transform Mexico's armed forces into latino Prussians. Belt-tightening will limit future purchases; and transport, communications, intelligence, and training are but a few of the areas in which vast improvements must still take place.

Nonetheless, its leaders seem increasingly aware of their nation's strategic position as evidenced in December 1980 when the army held its annual maneuvers, involving some 25 battalions and 15,000 men, near the Guatemalan border to (1) familiarize soldiers and officers with the terrain, (2) ferret out encampments of Guatemalan insurgents who seek sanctuary in Mexican territory, and (3) ''show the flag'' to the Guatemalan military lest it consider meddling in Belize, a former British colony.

Long before being called upon to repel invaders, the army may be dispatched to quell strikes and demonstrations triggered by the imposition of an austerity program that will surely entail budget cuts, limited wage hikes, and diminished subsidies on food and other essentials.

During the Napoleonic wars, ambitious soldiers reportedly carried a marshal's baton in their knapsacks. No presidential sashes have turned up in the briefcases of Mexico's military men. Still, a confluence of factors - vulnerable oil fields, turmoil in Central America, and the inevitable flare-up of social discontent - will make them more important during the next presidential term, to begin on Dec. 1.