A new entry into the expansion sweepstakes has been heard from, and in grandiose terms. Those big movers of the New Jersey Sports Exposition Authority -- the people who charmed the NFL New York Giants into moving to East Rutherford, N.J., and whose flourishing horse racing plants are giving the New York tracks a pain -- are now ogling a National League baseball franchise.

As latecomers to the list of regions tilting for an expansion team, the New Jersey folks have come up with a sort of supplemental starting fee. They are pledging to deliver 2 million attendance a year for the next five years, says the New York Times, and promising to build a 55,000-seat stadium in one of three northern New Jersey counties with a population total of 5.6 million.

How's that for an irresistible proposal? In truth, not so overwhelming, not such a big deal, and hardly a serious threat to derail the franchise hopes of Washington and so many other cities seeking an expansion team.

The major league planning committee, which will meet Dec. 9 in San Diego and make the definitive recommendations on expansion, could be vastly unimpressed with the New Jersey offer, and even ask what else is new. Fact is, there is no magic about 2 million attendance. It has become commonplace, not much to boast about, with 11 of the 26 big-league teams surpassing that figure last season.

There is a fascinating gimmick attached to that 2 million attendance guarantee. The Jersey people aren't really guaranteeing they will put 2 million fans in the park. What they are going to do is recompense the club owner if his team doesn't draw 2 million. The idea is that his stadium rent will be lowered to cover the gap in any attendance shortfall. Aha, a taxpayers' subsidy. Baseball on welfare. Peter Ueberroth would scream at that.

The New Jersey people are proud of their offer. "It's bankable for any prospective club owner," said one state official, who points out demographic studies project a 2.6 million attendance. But baseball people have learned to beware of demographic studies. Many years ago, when one local survey put the potential Kansas City drawing area for baseball at 1 million, one native quipped, "They must be counting cornstalks and tractors." Also, the New Jersey people could find George Steinbrenner, principal partner in the New York Yankees, very adverse to a move to put a team in northern New Jersey. That area happens to be strong Yankees territory, which they have vigorously promoted for many years. A number of Yankees players live there. The Yankees might concede Long Island to the Mets, but they claim New Jersey as their turf.

Steinbrenner has veto power over an American League franchise within 30 miles of New York and would have the help of fellow AL club owners on turning down a National League intrusion in northern New Jersey, which could hurt AL attendance in New York, and thus their own pocketbooks. Eight AL votes against it. A simple league majority could keep NL baseball out of Jersey.

And only the most insensitive club owners would vote a third team in the New York area when Washington and many other cities are panting for just one club. Nor is it remote that Congress could get mad and take hostile action at the game's antitrust exemption, which is an anachronism, anyway.

The hope of Washington and other bidders that the expansion process could be sidestepped and a team gained simply by buying the foundering San Francisco Giants franchise has now become sheer fantasy. Expansion is the only route.

Bob Lurie, principal owner of the Giants, is rightfully refusing to play another season in Candlestick Park, that wind tunnel that features discomfort for both players and fans. It was a slim hope anyway, that Jack Kent Cooke, for all his wealth, would buy the Giants for Washington. An eminent citizen of San Francisco, Lurie would find his hometown unlivable were he to sell the team cross country.

Washington probably has moved to the top in its bid for an expansion team, ahead of Denver, although two expansion cities eventually will be named. Washington's financial backing is formidable, its political and stadium conditions meet all the criteria and the climate for prime consideration is altogether favorable.

Washington's is a two-pronged thrust, with Cooke leading one charge and a hefty real estate combine of Oliver T. Carr, James Clark and Ted Lerner on the other flank. Who wins, in the event Washington is awarded a team? Probably The Group if it becomes a popularity contest. Probably Cooke, if the NL opts for the assurance of sports savvy and staying power, along with Fortune 500 resources.

In either event Washington would be assured responsible ownership. Individually, members of the Carr-Clark-Lerner unit have been winners in other enterprises and, like Cooke, boast all the necessary capital. For Washingtonians, Cooke's Redskins operations have been a plus, and either side of the coin would be acceptable.