MILWAUKEE — To own a professional sports team is so often to achieve your heart’s desire.

Last year, two New York City hedge fund owners purchased the Milwaukee Bucks, a down-at-the-heels N.B.A. team. The new owners smiled, took a victory lap around this handsome lakeside city and laid down their terms.

We’ll keep the Bucks in Milwaukee, the owners said, if the public foots half the cost of a $500 million arena. (The owners spoke of their “moral obligation” to the city and pledged $100 million toward their arena, with the remainder coming from other private funds.) N.B.A. officials acted as muscle for the owners and warned that if Wisconsin did not cough up this money within a year’s time, the league would move the team to Las Vegas or Seattle.

These opening feints were right out of the professional sports owner handbook. From start to desultory end, Milwaukee offered a case study in all that is wrong with our arena-shakedown age.

Gov. Scott Walker signed a bill Wednesday to subsidize the arena, which could cost the public twice as much as originally projected. Echoing the owners’ arguments, the governor proclaimed that the arena, a practice complex and a promised “entertainment district” would spur a renaissance for downtown Milwaukee and attract tourists. Income taxes paid by the pro athletes, the governor said, would fill local coffers.