Some of the country's smartest political pros and pundits -- including Paul Taylor {"Will Hart's Demise Give Us the Late, Late Mario Scenario?" Outlook, May 24} -- are suggesting that the Democrats are headed for every political junkie's dream -- a major late entry into the race and perhaps a brokered convention. They say that both parties have weak or nonexistent front-runners, that the Big Boys are waiting for a deadlocked day in spring to arrive on the scene; and that the power brokers will step in at the end to anoint a nominee.

I hate to disappoint everyone, but a brokered convention or a successful late entry, at least for the Democrats, isn't going to happen. It won't happen for two good reasons -- the party can't afford it and the system won't allow it.

The most oft-cited reason that we are headed for a late entry/brokered convention scenario is that none of our much-maligned Democratic candidates (dubbed the Seven Dwarfs by the chroniclers) now in the race can possibly put together a majority of delegates by convention time in Atlanta. After all, the story goes, how can these candidates, most with single-digit name recognition, expect to become figures of such national stature as to lay claim to the nomination?

One need only go back to 1984 to realize how quickly "stature" can come to a candidate. About this time (June) in 1983, Gary Hart was less known than Jesse Jackson, Richard Gephardt or Michael Dukakis, yet a year later he came within a whisker of being the nominee. Hart's name recognition went from about 15 percent before the Iowa caucus to a household word after he beat Mondale in New Hampshire. If Mondale had not won either Georgia or Alabama on Super Tuesday in 1984, he would have been out of the race and the "dwarf" from Colorado would have been the nominee.

But, say the experts, Hart got there because he knocked off the heir apparent. There is no Mondale to beat this time. True, so let's go back a decade. In 1976 there was no prohibitive front-runner, yet Jimmy Carter, who was less known in June of 1975 than Simon, Biden, Babbitt or Gore are in June of 1987, won the nomination.

Both Carter and Hart were beneficiaries of the current system of selecting candidates that grew out of the reform movement of 1968 -- a movement that for all intents and purposes removed the "brokers" from the party. Pre-1972, people like Mayor Daley in Chicago and some very strong governors could control their delegates and award them to a candidate. In fact it was five governors who delivered brokered delegates to JFK, putting him over the top at the 1960 convention.

The reform movement eliminated brokers and paved the way for more and more primaries as a method of selecting delegates. These primaries have been steadily moving up earlier and earlier in the selection window. (In 1968, 1 percent of delegates were chosen by March 15. In 1988, 54 percent will be chosen by March 15.) The proliferation of earlier contests has increased the importance of both the Iowa and New Hampshire contests. In order to generate the momentum needed to win the nomination, candidates must do well in Iowa and/or New Hampshire or else.

The front-loading system, coupled with the importance of Iowa and New Hampshire, has had two effects. It makes unknown candidates known very fast (Carter and Hart) and it narrows down the number of candidates in the field very quickly (four of seven 1984 candidates were out of the race in the first four weeks after Iowa).

Not only will these dynamics be in place in '88, but they will be even more powerful. The system will make any of the Seven Dwarfs look like giants in a matter of days, and retire most of the rest within a matter of weeks. So instead of seven or eight dwarfs, the Democrats will have two or three very big men left to fight for the nomination. And if any brokering takes place it will take place between these remaining candidates (and perhaps a few of the ex-candidates) and not with any brokers (let's face it, there are no brokers anymore).

What brokering among candidates takes place will happen before the convention. Conventions are no longer the end of the nominating process but the beginning of the fall campaign. They are usually organized by the nominee-to-be to put his best foot forward and all that. Neither party can afford to be seen fighting or dealing during those glorious four days of free TV.

So if the Big Boys (Cuomo, Nunn) decide to run (as many hope they will if the selection process bogs down), they will have to get in the race by the fall or watch it go by. One of the candidates in this race by Thanksgiving will be the nominee. If Cuomo or Nunn wants to be the nominee, he'll have to get his delegates the old-fashioned way -- earn them at the polls. The Democratic nominee won't be decided in July in Atlanta. He will be chosen where he usually is, in or around the Pennsylvania primary in April. The writer, a political consultant, was national campaign manager for the Mondale-Ferraro presidential campaign