Suddenly, Gov. Arnold Schwarzenegger's biggest problem isn't a budget deficit. It's a surplus.

The $15 billion bond California voters approved last week is far more than is needed to retire about $9 billion in budget debt accumulated to date.

Schwarzenegger's plan is to use some of the borrowed money to repay the debt, holding the remainder in reserve. He then hopes to spread those leftover bond proceeds over the next two years, easing the state's path back to a balanced budget.

In essence, the governor has a three-year plan to return state government to the black. He would use some of the borrowed money this year, then a little bit less next year and finally, in the third year, balance the budget with no borrowed money at all. The bond funds would help fill the gap while he slows the projected growth in spending and allows tax revenues, spurred by economic recovery, to catch up.

Schwarzenegger hasn't hidden the fact that his plan would take three years to complete. But neither has he advertised it widely. He likes to portray himself as a man of action. Taking three years to solve a problem, even one as difficult as this, doesn't fit into that image.

But now it is crucial that Schwarzenegger begin to fill out the details of his plan and market it to the Legislature, and to the public. If he fails to do so, he risks seeing the whole thing unravel.

Here is the problem. In the coming year, even after paying off the old debt, the governor is facing a new, projected $15 billion gap between spending and revenues. To close that gap, he is asking lawmakers to approve about $8 billion in spending cuts to state and local government services, along with an assortment of other transfers and loans. And he says he is willing to use about $3 billion of his bond proceeds to fill out the equation.

That would balance the books for one year, but wouldn't solve the long-term problem. Because Schwarzenegger is using borrowed money and other temporary measures, some of the projected deficit pops up again in the following year. If all goes according to plan, the new deficit will be significantly smaller than the current one. He then uses some more spending cuts and the final $2 billion in bond proceeds to close the gap one more time.

Finally, in year three, projections show revenues climbing to the point that they match projected spending. No more need for borrowed money.

But for Schwarzenegger's plan to have any chance of succeeding, it is essential that he hold back the final $2 billion in borrowed money for the year after next. If he allows lawmakers to spend that money in the coming year, they will be making commitments neither they nor he can sustain. The spending will continue, but the borrowed money will be gone. The state will be right back where it was a year ago.

Pulling this off is going to take all of Schwarzenegger's powers of persuasion. He is asking lawmakers to reduce grants to the aged, cut payments to doctors and hospitals that care for the poor, trim services for the home-bound disabled, cut spending on the universities, suspend the constitutional guarantee for public education, and divert money from local government. And while they are doing all of that, taking painful votes that will anger their constituents and test their commitment to principles, he wants them to ignore that he is sitting on $2 billion from the bond that he must save for the year after next.

The only way that can possibly make sense is if Schwarzenegger gets beyond the traditional year-to-year outlook in Sacramento and lays out in considerable detail how his three-year plan would work each year until the budget is balanced again. He needs to tell the public, and the Legislature, what he expects the picture to look like a year from now, and how much he expects to be able to spend on the broad categories of government: health, education, welfare, transportation, prisons. It would be even better if he could get lawmakers to pass legislation that helps to lock in that difficult path to a balanced budget.

This is high finance, hard to capture in catchy slogans and television commercials. Not everyone will pay attention or be able to grasp the details. But Schwarzenegger surely has the skills to communicate the basic point: This is a three-year plan that requires strict discipline.

Getting that message across will be even more important than the bond campaign the governor just completed. If Schwarzenegger fails, and allows the budget to spin out of control again, even after borrowing $15 billion, his stewardship of California's finances will ultimately be remembered as even worse than his predecessor's.