I've been critical of my local State Senator, Darrell Steinberg, but I'm with him on this one. In fact, were I Steinberg, I'd be mad as a hornet and going round the Capitol building putting devil horns on the pictures of the Governor.
What happened was this: Jerry Brown came into office claiming that he would fix California's budget problems. To do this, he would both chop out a bunch of spending for low-income Californians, particularly children and seniors, and raise taxes. Unfortunately it takes only a majority vote of the Legislature to cut services, but it takes a 2/3 majority to raise taxes. The Governor opened negotiations with the Republicans to get the four Republican votes (two in the Assembly and two in the Senate). But these votes were hard to come by. In fact, they never showed up. Nothing, nada. They negotiated, yes, but every time they came close to agreement, the Republicans came up with more demands. Pension "reform", gutting environmental regulations, and so on. Barely more than 1/3 of the Legislature, they wanted all of the Republican Party platform.
When it became clear (along about March for most people) that the Governor wasn't going to get his four Republicans, it also became clear that the Democrats were going to have to do the budget on their own. It's not a pretty budget--it cuts services, kicks the can down the road, moves money around--but it was a budget. The Governor vetoed it, claiming that it wasn't realistic. Well, it may not have been the best budget, certainly not one I liked, but it was more realistic than the Governor's.