Mile-high milestone

When he first announced his intention last year to run for mayor of Denver, few observers would have given Federico Pena much chance of success. The mile-high city's mayor, after all, was the redoubtable William McNichols Jr., who was in his third full term. Moreover, Mr. Pena is Hispanic in a city that counts only 18 percent or so of its 490,000 residents as Hispanic. Thus, by winning the general election this week (after defeating Mr. McNichols in a primary), the youthful looking Mr. Pena has already left a sizable imprint on that city's political history.

There can be little doubt that Mr. Pena's victory will be closely studied by both major political parties as they gear up for the crucial 1984 national and state contests. In defeating an articulate opponent who was Denver's district attorney for ten years, Mr. Pena becomes one of a growing number of Hispanic-American political leaders in the Southwest and Western US. Mr. Pena won by hammering together a coalition of Hispanics, blacks, women, labor unions, and younger whites.

One other facet of the Denver election deserves special attention. That is the way the campaign between Mr. Pena and District Attorney Dale Tooley was waged. In sharp contrast with the municipal election in Chicago this year, the racial issue was never a major factor in the Denver contest. Throughout his campaign, in fact, Mr. Pena, a lawyer, repeatedly stressed that the main issue was electing a candidate who had a ''vision for the city.''

Mr. Pena will now have his opportunity to show Denver residents what his sense of vision entails.

In the meantime, Denver has given the whole nation a vision of a close-fought but decent election contest.