It is a journalistic conceit that all elections must mean something. Most do nothing more than decide what name goes on the letterhead and the office door. Occasionally, an election may give a clue to a broader political trend or current, but the burden of proof is clearly on the trend-spotter, which is the self-assigned role for me today.

So let me begin with this trivia question: Who were J. Lindsay Almond Jr. and Robert B. Meyner and what was their historical importance?

I know the answer only because I looked it up. They were the men elected as governors of Virginia and New Jersey 28 years ago last week, when Dwight D. Eisenhower, like Ronald Reagan today, was the elderly gentleman in the first year of his final White House term.

Almond and Meyner served their states honorably in the '50s and then faded from the scene. Their victories in no way foretold the national succession of 1960, which saw the youthful Democrat John F. Kennedy take over from the aging and well-loved Republican Ike.

So history suggests there is every reason to be skeptical that the reelection of Gov. Thomas H. Kean (Republican) of New Jersey and the election of Gerald L. Baliles (Democrat) to succeed Democratic Gov. Charles S. Robb (D) of Virginia last week speak volumes about what will happen in politics when Reagan steps down in 1988.

But even if they are shaky guideposts to the future, their wins are instructive in themselves and conceivably of more import than most such off-year election results. Kean and Robb are leaders of their parties' younger generation and both are plausible -- if not likely -- choices for places on the national tickets.

Kean won a record-breaking 70 percent majority over a competent, attractive Democratic challenger. Kean carried majorities of blacks, union members and other normally Democratic voting groups, and powered his party to a takeover of the state assembly.

Robb was denied the possibility of a similarly impressive personal triumph by the archaic Virginia ban on reelection of governors. But he was the force propelling the election of Baliles and the Democratic ticket including the South's first black lieutenant governor and the state's first woman attorney general.

The professional campaign consultants in the two winning races (Roger Stone for Kean and David Doak for Baliles) both commented on the parallel features of the two races. The elections, they said, once again demonstrated the voters' disdain for party labels. Kean won as a Republican in a state with two Democratic senators; Baliles won as a Democrat in a state with two Republican senators.

Stone calls it evidence of "dealignment" or the breakdown of party loyalties. Doak agrees, adding only that it is "at least 15 years old."

In such an atomized political environment, candidates can -- and must -- build what Stone calls "temporary coalitions" that cut across the old-generation patterns and loyalties. Kean and Robb-Baliles found similar formulas, emphasizing their fiscal conservatism (as measured by opposition to tax hikes) and their progressiveness on social and racial issues.

Despite the notably nonpartisan campaigns the winners ran, their parties have legitimate reasons for encouragement. As Doak said, Robb and Baliles showed that once voters are assured "you're not going to tax and spend them to death, they are very comfortable voting for Democrats who put education at the forefront and bring minorities into the mainstream."

In mirror image, Stone said, blacks and feminists, teachers and union members in New Jersey were willing to judge Kean on his record on issues of importance to them and to support him "as strongly as the conservatives who back Reagan in this state."

Kean reached well beyond the Reagan coalition, and Baliles, with Robb's help, mined votes from Reagan supporters. Thus, a variety of pollsters and consultants from both parties (Peter Hart, John Deardourff, Greg Schneiders, among others) have concluded that the off-year elections demonstrate Reagan's "irrelevance" to elections from this point onward.

I am not so sure. The kind of consensus politics Kean and Robb-Baliles practice works best in times and places of economic growth. And Reagan is ultimately more responsible than any other politician for the maintenance of a healthy economy. If it goes on the rocks during his second term, 1988 will see a nastier, more partisan and polarized fight than either Virginia or New Jersey witnessed this year.

What strikes me as significant is that both the Kean and the Robb-Baliles administrations dealt seriously and effectively with the governmental challenges of their states during the past four years. Their victories may not point the way to either party's national ascendancy. But they do carry the healthy and important message that the voters in large numbers recognize that kind of service and reward it.