C'ardenas taps discontent as he battles ruling party. MEXICO'S `MAN OF THE MOMENT'

``Don't let us down, Cuauht'emoc. Don't leave us alone,'' a man perched on a lamp pole called out as the bus carrying Mexico's leading opposition figure Cuauht'emoc C'ardenas maneuvered through the crowd. It is hard to imagine a less likely man to have experienced political success in this country. Analysts have speculated for years over who might one day stir the hearts and minds of Mexicans. They never pictured someone like Mr. C'ardenas.

Except for the magic of his name - his father, L'azaro C'ardenas, was a beloved President (1934-1940) - C'ardenas possesses none of the attributes that normally make a successful politician here.

At rallies, he watches the crowd with a stern face. He is a wooden speaker. He does not speak about the normal stuff politics is made of here. Instead of promising new roads, new schools, or higher wages, he speaks of democracy, party unity, and the need to peacefully defend the ``legality of the vote.''

Nearly three months after the July 6 highly contested presidential elections, in which C'ardenas was declared the runner-up to the ruling party's Carlos Salinas de Gortari, he is still drawing huge crowds. This has baffled analysts almost as much as his electoral showing.

The newest campaign was a whistle-stop tour through Veracruz State to support candidates running for mayor on his left-of-center National Democratic Front (FDN) ticket.

His stated goal is to win power from Mexico's ruling Institutional Revolutionary Party (PRI) and restore the principles of Mexico's revolution - nationalism, democracy, and progressive social programs.

``You cannot let the people down,'' said C'ardenas before his bus pulled into Cardel, just north of the port of Veracruz.

Yesterday's local vote in Veracruz was the first since July 6 and is seen as a test case for Mexico's new political forces. C'ardenas is trying to bring the diverse parties supporting him into a more unified alliance, insisting the only way they can win elections is to join forces.

The vote, results were not available at press time, was also seen as a test for the PRI, still bruised from national elections in which even its bare majority was seriously questioned because fraud became the issue.

Leading ``Pri-istas'' - supporters of Salinas's program of modernization - have accused C'ardenas of representing the past, a return to ``nostalgia.''

It is true most Mexicans remember his father who put into place many programs now considered the core of the revolution - land reform, government ownership of key industries such as oil, and social programs to benefit Mexico's poor.

No party has successfully taken on the PRI, now in its 60th year of power. But with C'ardenas, there is a sense that this is more than politics. ``He has a mission,'' one political observer said.

``Consider, if you lived in the White House at age six [months] and your father were Washington, what would you be like?'' said Hermenegildo Castro, a reporter who covered C'ardenas's campaign.

C'ardenas was only six months old in 1934 when his father took office as president of Mexico, the youngest ever at 38. He became a civil engineer and worked with his father on the Rio Balsas development project, before starting on his own career in public administration - always as a member of the PRI. C'ardenas served as deputy minister of forestry, was elected a senator, and in 1980 became governor of Michoac'an State.

The elder C'ardenas was considered something of the ``puritan of the revolution,'' according to anthropologist Roger Bartra who worked with both the father and son on the Rio Balsas project. In the L'azaro C'ardenas home, they did not serve alcohol, and no one smoked. C'ardenas himself does not smoke and drinks only occasionally.

Many see this influence in his most controversial actions as governor. He discouraged prostitution by closing red-light districts and enforced a federal law prohibiting liquor sales on weekends. The measures had their strong critics. The next governor reversed the situation.

There is one gauge of how people judged C'ardenas as governor. In July, he won 70 percent of the ballots in Michoac'an.

He was always rated a competent and honest administrator but earned few rave reviews, one more reason why his current success has stunned many.

Political analyst Adolfo Aguilar, now at the Carnegie Institute in Washington, attributed C'ardenas's success to his cautious style. ``He is a patient and astute politician.''

C'ardenas insisted he knew people would respond to his challenge to the PRI, and that he was only tapping into public discontent. But he does say, ``in this case the political, social and economic situation had to coincide with a situation of an individual nature.'' In other words, he was the man of the moment.