By Kevin Fagan

State Assemblyman Tom Ammiano is so high (pun just in fun) on the chances of Proposition 19 passing in next month’s general election, legalizing adult marijuana use, that he’s already trying to get the state ready for oversight.

The San Francisco Democrat introduced bill ABX6 9, which calls for a uniform statewide regulatory system for pot, to be under the control of the California Dept. of Alcoholic Beverage Control. And on Wednesday he held a press conference outside the State Building in downtown San Francisco to tout it.

Several leaders of the Prop. 19 movement chipped in their support, noting that while the initiative gives local governments the control to tax, regulate and control pot, the state will have to come up with some more guidance of its own — which they said Ammiano’s bill would provide.

Ammiano said he wants to head off any of the same sort of statehouse confusion that followed state voters’ passage in 1996 of Proposition 215, which legalized medical marijuana usage.

“It’s always better in Sacramento if you think ahead,” Ammiano said. “It always takes awhile to get traction there.”

E-mail Kevin Fagan at kfagan@sfchronicle.com.