The states, Justice Brandeis famously pointed out, are the laboratories of democracy. And it’s still true. For example, one reason we knew or should have known that Obamacare was workable was the post-2006 success of Romneycare in Massachusetts. More recently, Kansas went all-in on supply-side economics, slashing taxes on the affluent in the belief that this would spark a huge boom; the boom didn’t happen, but the budget deficit exploded, offering an object lesson to those willing to learn from experience.

And there’s an even bigger if less drastic experiment under way in the opposite direction. California has long suffered from political paralysis, with budget rules that allowed an increasingly extreme Republican minority to hamstring a Democratic majority; when the state’s housing bubble burst, it plunged into fiscal crisis. In 2012, however, Democratic dominance finally became strong enough to overcome the paralysis, and Gov. Jerry Brown was able to push through a modestly liberal agenda of higher taxes, spending increases and a rise in the minimum wage. California also moved enthusiastically to implement Obamacare.

I guess we’re not in Kansas anymore. (Sorry, I couldn’t help myself.)

Needless to say, conservatives predicted doom. A representative reaction: Daniel J. Mitchell of the Cato Institute declared […]