Remember the Texas economic miracle? In 2012, it was one of the three main arguments from then-Gov. Rick Perry about why he should be president, along with his strong support from the religious right and something else I can’t remember (sorry, couldn’t help myself). More broadly, conservatives have long held Texas up as a supposed demonstration that low taxes on the rich and harsh treatment of the poor are the keys to prosperity.

So it’s interesting to note that Texas is looking a lot less miraculous lately than it used to. To be fair, we’re talking about a modest stumble, not a collapse. Still, events in Texas and other states — notably Kansas and California — are providing yet another object demonstration that the tax-cut obsession that dominates the modern Republican Party is all wrong.

The facts: For many years, economic growth in Texas has consistently outpaced growth in the rest of America. But that long run ended in 2015, with employment growth in Texas dropping well below the national average and a fall in leading indicators pointing to a further slowdown ahead. In most states, this slowdown would be no big deal; occasional underperformance is just a fact of life. But everything is bigger in Texas, including inflated expectations, so the slowdown has come as something of a shock.

Now, there’s no mystery about what is happening: It’s all about the hydrocarbons. Texans like to point out that their state’s economy is a lot more diversified than it was in J.R. Ewing’s day, and they’re right. But Texas still has a disproportionate share of the U.S. oil and gas industry, and it benefited far more than most other states from the fracking boom. By my estimates, about half the energy-related jobs created by that boom since it began in the middle of the last decade were in Texas, and this extractive-sector windfall accounted for about a third of the difference between growth in Texas and growth in the rest of the country.