But in that case, how can we evaluate Trump’s economic policies? The answer is, by looking at how those policies were supposed to work, and comparing that with what’s actually happening.

Let me damn the 2017 tax cut with some faint praise: While the logic of the Trump trade war is completely muddled — never mind how it’s supposed to work, it’s not even clear what it’s supposed to achieve — the drafters of the tax bill did have a theory of the case. The story went like this: Lower taxes on corporations would lead to a huge surge of investment, which would raise productivity, which would eventually be passed on to workers in higher wages.

By the way, the idea that workers would see an immediate benefit was always obvious nonsense, and sure enough, they didn’t. In fact, adjusted for inflation, the hourly wages of ordinary workers were slightly lower in May than they were a year earlier.

Anyway, when I say a huge surge in investment, I mean huge. Last year I looked at estimates from the Tax Foundation, the only independent institution (well, supposedly independent, anyway) willing to endorse highly optimistic assessments of the tax cut. Those estimates, it turned out, implied a boost in business investment of around $600 billion a year, or 3 percent of G.D.P.

Nothing like that is happening, and leading indicators of business investment, like orders of capital goods, show no sign of an investment boom ahead. Corporations have gotten a really big tax cut: The tax take on corporate profits has fallen off a cliff since the tax cut was enacted. But they’re using the extra money for stock buybacks and higher dividends, not investment.

As a result, there’s no reason to believe that the U.S. economy’s potential growth — the rate of growth it can achieve on a sustained basis — will rise from the 2 percent or less expected by most analysts. The tax cut has been good for stockholders — about a third of whom are foreigners, by the way. Working Americans, not so much.

So how is the Trump economic policy doing? The tax cut is utterly failing to deliver on its advocates’ promises. It’s early days in the trade war, but the administration’s strategy seems designed to inflict maximum self-harm, and first reports suggest that trade conflict is leading to reduced, not increased, investment.

Against that background, how much should we care about whatever headlines are generated by the next set of growth numbers? Very little, if at all. (To be clear, this statement also applies if the quarterly numbers come in worse than expected.) Short-term growth is noise, signifying nothing.