Absent some new source of money or a significant cut in its cost, a new ballpark for the Red Sox seems doomed to remain a field of dreams.

The team is right in saying that a new park is necessary. Closing in on its 90th birthday, Fenway Park is too small, too cramped and too uncomfortable. Few fans - that is to say, people who actually go to games, rather than watching them on TV - will mourn the passing of the old park.

Getting a new park built, however, is a tough proposition.

The Sox have noted, indeed, almost boasted, that at $627 million the new stadium will be the most expensive ever built.

This is not a good thing.

In most businesses, spending more than your competitors to provide the same product is a problem. The Sox's original rationale for the new, larger park was that it would help them competitively. But the cost of this stadium should raise a red flag; instead of helping the Sox, the costs may overwhelm them.

Since 1991, 13 new ballparks have been built or are now under construction. Their average cost has been $298 million (the most expensive of which is San Diego's, a $411 million project scheduled to open in 2001). Why should a new Fenway Park cost twice as much to build?

The incredibly high cost is driven by the team's insistence that it remain in the Fenway itself. Land in the area is expensive to buy and, because it's landfill, it's expensive to build on. The complexity of building in a dense urban area adds even more cost.

Indeed, if the Sox were able to build at Fort Point channel, a location near South Station they had eyed several years ago, the cost of the new ballpark would plummet.

A confession: I live within walking distance of Fenway Park. I'd just as soon have the team stay close by. But is Fenway really such a great location? Is it $300 million better than other local sites?

That question is particularly relevant because the team is asking the public to finance close to half the project. It's the price of the new park that drives that request.

The Sox have proposed that the city and state kick in $275 million. Of this amount, only $53 million is truly unobjectionable: It's for infrastructure such as new roads and enhanced public transit. That's the kind of stuff for which government usually pays, and there's little question that it should step in to help the Red Sox here.

The remaining $222 million includes $82 million to build two new parking garages and $140 million for land. The Sox want the state to pay for the garages and have asked the city of Boston to buy the land.

The threshold question, of course, is why should the city or state pay at all? We expect private businesses to pay their own way. Why treat the Red Sox any differently?

The rationale the Red Sox offer is that there are unique and significant economic spinoffs from the team's presence. Fans coming to see a game spend money on other things as well. One might eat in a local restaurant. Another might stay at a nearby hotel.

That's true, but it's a phenomenon that is hardly unique to the Red Sox. There are significant economic spinoffs from almost all kinds of businesses (workers at Gillette, for instance, also eat at nearby restaurants). Indeed, most independent analyses of public investments in professional sports teams suggest that they show, at best, a modest return.

Let's be truthful here. It's not cold, dollars-and-cents economic benefits that justify public financing. Instead, the rationale is almost spiritual.

The Red Sox's most powerful claim is on our hearts, not our pocketbooks. It's a claim that is tied to tradition, to shared experience and to a never-ending frustration with the team's inability to win a World Series.

It's a strong claim. But is it strong enough to justify the taxpayers risking $222 million to support what is essentially a private enterprise?

Moreover, while the state will presumably get parking revenues in exchange for building the garages, the city of Boston does not fare well under the Sox's plans.

In exchange for Boston spending $140 million to buy the land, the team says the city might realize another $5 million annually in new property taxes. Even if Boston could borrow the $140 million at 5 percent, those new property taxes don't even cover the city's interest costs.

So where does the money come from?

The team suggests that Boston might increase taxes, perhaps by boosting the hotel tax or creating a tax on parking. That's doubtful. Boston is desperately short of resources for high political priorities such as education and affordable housing. What politician could credibly claim that the Sox's needs are more important?

Indeed, it seems increasingly clear that the plan now on the table won't fly.

The Sox say that they are tapped out. Having committed to fund $352 million, anymore is impossible. The real culprit is not the team, but the gigantic cost of a new stadium. Until that is resolved - or until the Sox, their protestations aside, somehow find more money - fans will continue to suffer in the hallowed but dank corridors of Fenway Park.

Tom Keane writes weekly for the Boston Herald. He is reachable at tomkeane@tomkeane.com.