The Supreme Court of Texas heard arguments Tuesday in a case challenging the constitutionality of the state's primary business tax, a case that could have major implications for the way the state funds schools.

The 2006 tax swap — lowering local school property taxes and creating a new business tax to make up the difference — is at the center of Texas' current budget troubles. The architects are still pointing fingers over what and whom to blame for the state's “structural deficit.”

Lawmakers are waiting for Comptroller Susan Combs to forecast exactly how much money the state will collect between now and August 2013 so they can write a two-year budget that spends no more than that. It's not exactly like opening the envelopes at the Oscars, but the Capitol community will be hanging on her every word. If history is a guide, her estimate of revenues will be closer to the bull's eye than the Legislature's estimate of spending. But this is a dark art; accuracy can be elusive.

Every candidate vying for a legislative seat knows what lies ahead in 2011: a budget shortfall of at least $11 billion, probably higher, and state agency cuts to save as much of that amount as possible. But new revenue is a possibility as well, even if lawmakers are expert at the old sleight of hand, employing creative accounting and semantic trickery to avoid stepping on that political third rail, the tax hike.

Will there be enough money to cover the current state budget? "Fortunately, it's too early to tell," jokes House Speaker Joe Straus. He and other state leaders are well aware of the numbers, and although they think it's not yet time to act, they're focused on the big question.