While we’ve gotten used to Tea Party primary challenges to popular and seemingly secure Republican incumbents, something unusual is happening in Kansas. Governor Sam Brownback is facing an organized revolt from centrist Republicans, over 100 of whom just endorsed the presumptive Democratic nominee for governor, so disgruntled are they with the effects of Brownback’s rule.

In many ways, Brownback’s term has been a perfect experiment in Republican governance. Take a crusading conservative governor, give him a legislature with Republican super-majorities so he can do pretty much whatever he wants, and let him implement the right’s wish list. The result was supposed to be a nirvana of economic growth and budgetary stability. But the opposite happened.

The disastrous results of Brownback’s economic and fiscal policies demonstrate that it’s one thing for your average Republican to go around saying things like “cutting taxes raises revenue!” even if nearly every economist agrees that the idea is absurd (Greg Mankiw, chairman of the Council of Economic Advisers under George W. Bush, famously called the purveyors of this idea “charlatans and cranks”). It’ll never really be tested, at least not in a context where there aren’t so many other variables at play that any inconvenient results can be explained away. Republicans know that it’s bogus, but they like the way it sounds; after all, who wouldn’t love a free lunch? But if you bet a single state’s future on the idea — and you have the power to take it to an extreme — you’re going farther than anyone in Washington ever has to go.

That’s what Sam Brownback did. In 2012 and 2013, Brownback and Republicans in the legislature cut income taxes twice, eliminated taxes on corporate profits that are “passed through” to individuals (making it the only state that does this), and since they’re Republicans, made changes to the tax code that had the effect of raising taxes on the poor (the Center on Budget and Policy Priorities has a good explanation of the tax changes and their effects). The governor has said his goal is to eventually eliminate the income tax completely.

And what happened? At a time when most states are seeing higher revenues as the country recovers economically, Kansas’ revenues have plummeted. The result has been cuts to schools, cuts to higher education, cuts to libraries, and cuts to local health centers. Kansas’ job growth and income growth are lagging the nation’s. In response to the fiscal difficulties, Moody’s recently lowered the state’s bond rating.

When he was elected in 2010, everyone knew Sam Brownback as a social conservative crusader, someone who’d fight to eliminate reproductive rights and campaign against same-sex marriage, and doesn’t believe in evolution. In an overwhelmingly conservative state, you can act on those issues without undermining your support, both because people agree with you and because the Constitution offers some constraints to how far you can go. But when you buy into some of the more fanciful conservative ideas about economics, things had better work out. If your tax cuts send the state into a fiscal crisis, the pain of dealing with it is going to be felt by everybody.

There’s a larger context to this revolt of moderate Republicans, which is that the Kansas Republican Party has been in a state of unending civil war between its social conservatives and its more moderate business conservatives for the last couple of decades. In his 2004 book What’s the Matter With Kansas?, Thomas Frank described “homemade slander campaigns startling in their barbarity” within the GOP, and concluded, “The bitterness persists today, poisoning political activity right down the roots of the grass.” That was a decade ago, and what’s remarkable isn’t just that the battle continues, but that in this extremely conservative state there are still moderate Republicans left to fight.

When he was elected governor, some Washington conservatives touted Sam Brownback as a future presidential contender. Once he implemented the conservative economic agenda and showed what a dynamic economy and pleasing government balance sheet it produced, he’d be able to take the message nationwide as a demonstration of the power of conservative ideas. Nobody’s saying that anymore. Brownback is trailing his probable Democratic opponent. In a state as conservative as Kansas (where Mitt Romney beat Barack Obama by 22 points), you have to screw up pretty badly to be in that position. And saying, “hey, didn’t we all agree that tax cuts raise revenue?” probably won’t bail him out.