Cost overruns were hardly unique to Safeco, which was completed in 1999. And neither was the solution of who would pay them: As with most recent deals, the team was contractually bound to cover overruns as part of its agreement with local and state officials to get a stadium financed largely by taxpayers.

Washington won’t be so lucky. Under last year’s agreement with Major League Baseball that returned professional baseball to the city, the District said it would absorb all overruns in building a ballpark for the Nationals, unless the extra cost was caused by last-minute enhancements demanded by the team or baseball.

The debate over the ballpark’s price has focused on whether it should be built on the Anacostia waterfront or adjacent to Robert F. Kennedy Memorial Stadium, and it has been based on rising cost projections for the stadium and surrounding infrastructure. The D.C. Council approved $535 million for the project, not counting financing fees—more public money than has ever been spent on a professional sports stadium. Mayor Anthony A. Williams (D) has promised to limit the city’s investment to the amount approved by the council, even as estimates have risen to $667 million or higher if underground parking is included.