Updated

The tournament that began with the lure of a billion-dollar bracket will come to a close at a billion-dollar stadium outside of Dallas.

Big as March Madness and the Final Four have become, they're not big enough to blot out the storm clouds on the horizon. The NCAA has issues looming — among them, the possible unionization of players and a lawsuit challenging the NCAA's ban on paying players.

If the NCAA loses either case, it would threaten almost everything. That includes its most lucrative and intoxicating event: The basketball tournament, which is celebrating best-in-a-generation TV ratings, a record number of overtime games and a staple of big-name programs — Florida, Wisconsin, Connecticut and Kentucky — that made it through hours of entertaining action en route to the Final Four.