SACRAMENTO -- Last year, as Gov. Jerry Brown hammered out final details of the state budget, he huddled around a conference table with three of the most powerful people in state government: The Assembly speaker, the Senate leader -- and Joe Nunez, chief lobbyist for the California Teachers Association.
California was on the edge of fiscal crisis. Negotiations had come down to one sticking point: Brown and the legislators would balance the books by assuming billions of dollars in extra revenue would materialize, then cut deeply from schools if it didn't.
Nunez said no.
Opposition from the powerful union, which had just staged a week of public protests against budget cuts, could mean a costly legal challenge.
So the group took a break, and the elected officials retired to another room to hash out something acceptable to CTA while Nunez awaited their return.
It may seem unorthodox for an unelected citizen to sit with Sacramento's elite as they pick winners and losers in the annual spending sweepstakes. But few major financial decisions in California are made without Nunez, who represents what is arguably the most potent force in state politics.
The union views itself as "the co-equal fourth branch of government," said Oakland Democrat Don Perata, a former teacher who crossed swords with the group when he was state Senate leader.
Backed by an army of 325,000 teachers and a war chest as sizable as those of the major political parties, CTA can make or break all sorts of deals. It holds sway over Democrats, labor's traditionally ally, and Republicans alike.
Jim Brulte, a former leader of the state Senate's GOP caucus, recalled once attending a CTA reception with a Republican colleague who told the union's leaders that he had come to "check with the owners."
CTA is one of the biggest political spenders in California. It outpaced all other special interests, including corporate players, such as AT&T and Chevron, from 2000 through 2009, according to a state study.
In that decade, the union shelled out more than $211 million in political contributions and lobbying expenses -- roughly twice that of the next largest spender, the Service Employees International Union.
It since has spent nearly $40 million more, including $4.7 million to help Brown become governor, according to the union's filings with the secretary of state.
And CTA's influence, unlike that of other interests, is written directly into California's Constitution. More than two decades ago, the group drafted an initiative to guarantee public schools at least 40 percent of the general fund and waged a successful multimillion-dollar campaign for it. As author and defender of that law, the union established a firm grip on the largest chunk of the budget.
CTA since has used its institutionalized clout, deep pockets and mass membership largely to protect the status quo. The union's positions often align with those of the smaller California Federation of Teachers, but its resources are unmatched.
CTA has ferociously guarded a set of hard-won tenure rules and seniority protections, repeatedly beating back attempts by education groups to overturn those measures, increase teacher accountability and introduce private-school vouchers.
It has thwarted the agendas of governors and even President Barack Obama, whose administration has tried and failed to enlist California in its effort to make sweeping changes in the country's education system.