THE PROSPECT of professional baseball returning to the nation's capital is enough to quicken the pulse of even a lukewarm sports fan. The vibrant Washington area is a major-league region with an infrastructure and thousands of fans who are more than ready for a baseball franchise after being without one for more than 31 years. With Major League Baseball officials ranking the Washington area as a top contender for a relocated team, the D.C. Council is weighing questions about paying for a stadium, including financing options and the fiscal implications for the D.C. economy. The council's timing is about right.

Two years ago Mayor Anthony A. Williams pledged $200 million toward a downtown baseball stadium, which he regards as a great opportunity for economic development. Of course, the city's finances were in much better shape at the time, and the national economy was less wobbly. While enthusiasm for a baseball team remains high among lawmakers and residents, several key council members -- such as Chairman Linda W. Cropp (D-At Large) and Jack Evans (D-Ward 2), who chairs the finance committee -- are asking whether the District, with its fiscal strains and one of the nation's heaviest per-capita debt burdens, can realistically contribute up to $200 million to the cost of a stadium. The question of whether local governments should subsidize stadiums for major sports franchises is being debated across the country. That District legislators are weighing such concerns themselves is neither unusual nor unwarranted.

The mayor and supporters of a city-backed stadium-financing package have a responsibility to show how baseball would invigorate the city's economy and generate new revenue. They must also answer whether the costs outweigh the benefits of constructing a new stadium equipped with bells and whistles to attract corporate and well-off fans. Could the same funds, for instance, be better spent on other programs and projects? The mayor contends that much of the city's contribution would come from borrowing, not operating revenue. But how does that square with the city's already high debt burden? And would stadium-based revenue from anticipated taxes on concessions, parking, tickets and player salaries be sufficient to repay the city's loan? Lest the mayor forget, there's a good chance -- if other D.C. professional sports teams are any guide -- that many baseball players and team staff would live outside the District. If so, their salaries could not be taxed by the city.

The council and the public deserve to know exactly how the mayor proposes to make good on his pledge, especially with the city facing a much-talked-about "structural deficit." The city also needs to know more about the extent to which private sources, namely the prospective team owners, would contribute to a project that ultimately would accrue to their financial benefit. Now is as good a time as any to find out.