President Trump will, on occasion, talk about magic wands. As a general rule, though, the subject at hand is neither Harry Potter nor wizardry. It is, instead, manufacturing.

“Remember the statement by President Obama [that] you’d have to wave a magic wand?” he said at a rally in Michigan in December. “Remember the magic wand because of manufacturing?”

It was a reference to a comment from his predecessor, who, during the 2016 campaign, mocked Trump’s insistence that he’d bring back manufacturing employment.

“How exactly are you going to do that? What exactly are you going to do?” Obama asked. “There’s no answer to it. He just says, 'Well, I’m going to negotiate a better deal.’ Well, what, how exactly are you going to negotiate that? What magic wand do you have? And usually the answer is, he doesn’t have an answer.”

To that crowd in Michigan, Trump was bragging about 41,000 jobs being added in motor vehicle and parts manufacturing. It is a bright spot in manufacturing employment, boosted at that point by General Motors workers ending their strike.

But preliminary job numbers released Friday show that the year-over-year shift in manufacturing jobs was lower in December than in the first two years of Trump’s administration. It was the second-slowest year of growth for manufacturing since the recession.

The number of jobs still grew, up by 46,000 relative to December 2018. But the economy overall grew faster. Since the end of the recession, the density of manufacturing jobs in the economy has been flat. But from October to December, that density was lower than it has been at any other point on record, dropping below 8.45 percent of all employment. In December, it was 8.44 percent, higher only than October’s 8.43 percent — when the GM strike temporarily pushed manufacturing numbers down.

Since Trump took office, the economy has added 6.7 million jobs, 487,000 of them in manufacturing. That’s 7 percent of the total — a higher density than the last three years of Obama’s administration, when 262,000 of about 8 million jobs were in manufacturing.

Regardless, the density of manufacturing in the economy is still sliding. The lower graph above shows the problem. There was a resurgence of the density of manufacturing jobs as a percentage of the workforce from mid-2017 to the beginning of 2019. But as employment in manufacturing stalled last year, adding only 46,000 jobs, that density has slipped.

This was Obama’s point: The American economy has broadly shifted away from manufacturing, and there wasn’t much Trump could do to resuscitate it, with or without a magic wand.