What did Donald Trump do today?

He attacked the Federal Reserve for giving him what he wants.

Today, Trump blamed Federal Reserve Chairman Jerome Powell—who Trump himself appointed—for the failure of the United States economy to reach the 4% growth that Trump promised. In an interview with Fox Business, Trump said, "The world is slowing, but we’re not slowing, and frankly if we didn’t have somebody that would raise interest rates and do quantitative tightening, we would’ve been at over 4 [percent] instead of at 3.1 [percent]."

The Fed raises interest rates during normal growth so that it can lower them to ward off or shorten recessions. Keeping them artificially low is a bit like eating seed corn: it endangers the future in exchange for a very small return in the present. 

Trump's only hope of political salvation lies in being able to claim that the economy is doing well, although in reality it's on very much the same trajectory as it was under President Obama. This is why he has already used up the other two emergency tools that a president has at his disposal to revive a bad economy—massive tax cuts and protectionist trade barriers—at a time when the economy was already in reasonably good shape.

Neither attempt succeeded in getting the growth rate to 4%, although the tax cuts are already exploding the national debt, and Trump's trade war has gone about as well as actual economists expected it would.

But this week, the Federal Reserve signaled that it would give Trump his wish and stop raising interest rates—because the economy is now expected to weaken much faster, and it may be necessary to use the last of those emergency tools on an actual economic emergency.

Why should I care about this?

• Presidents don't have to be economists, but they do have to be willing to listen to them.

• It's wrong to blame other people for your failures.