Since President Trump took office, one of the manufacturing sectors with the fastest growing employment has been mining and oil-and-gas machinery, up 25%. One of the worst-off has been cut-and-sew apparel contractors, down 22%.
Neither performance, good or bad, can be tied to Mr. Trump.
The manufacturing sector has added about 1.4 million jobs since 2010, but the rate of growth has been anything but a straight line. Oil prices and the dollar’s strength have mingled with long- and short-term fluctuations to create a complex picture.
Boosting American manufacturing has been a central policy aim for Mr. Trump, as he has imposed tariffs on imports, sought to renegotiate trade deals and goaded companies into making products in the U.S. He has taken credit for the boom in factory jobs during his first two years in office, while critics blame him for a cooling in growth since January.
There is truth to both claims: The Republican-authored tax cut passed in late 2017 helped lift manufacturing in 2018, while the trade confrontation with China has muffled global growth, which has hurt U.S. manufacturing this year.
But Labor Department data shows many other forces are also at work. In many manufacturing sectors, fluctuations in jobs can be tied to industry-specific issues or the rise and fall of technology and automation. Macroeconomic forces such as global growth, energy prices and the strength of the dollar are also involved. Most of those are beyond the control of Mr. Trump—or any president.
“The president in aggregate probably has very little to do…with the medium to long term dynamics of how employment is doing. The president can really only affect it on the margin,” said Ernie Tedeschi, economist at Evercore ISI.
When Mr. Trump took office in 2017, the U.S. was in the midst of a manufacturing-employment recovery that began in 2010. Since the start of the decade, overall manufacturing employment has grown by 1.39 million, or 12%. Even so, the current number of manufacturing jobs in the U.S.—12.85 million—is about 6.7 million less than at its peak in 1979.
Manufacturing output has risen since then, nonetheless, because rising productivity over the last few decades enabled factories to produce more with fewer workers. Sectors including automobiles, apparel and food are using robots, machine learning and artificial intelligence to do the repetitive tasks once done by people, economists say, while existing workers focus more on higher-skilled tasks.
The job growth since 2010 hasn’t been steady, or spread evenly among its subsectors, according to Labor Department data. Three times this decade, momentum slowed: from mid-2012 into 2013, again in 2015 through 2016 and during the first half of this year. Each time, job losses in particular sectors or larger global forces drove the cool-off.
Here are some of the forces at work in top subsectors:
Long-term growers: Food is the second largest employer in manufacturing, and it has been growing since several years before Mr. Trump took office, reflecting weather, commodity prices and exports. Jobs in animal slaughtering and processing—which account for about a third of food-manufacturing positions—have grown solidly since 2015, by 9.8%.
Some of that pickup reflects a recovery in beef production after a drought swept over Texas and Oklahoma shortly after the last recession, according to David Anderson, an agricultural economist at Texas A&M University. He said increasing U.S. exports of pork along with rising profits at livestock companies tied to low corn prices also aided plant expansion. Such factors, Mr. Anderson said, “are having a bigger effect” than any specific administration policy.
In general, factory jobs tied to what Americans eat and drink have prospered. Positions at breweries, wineries and distilleries have grown every year this decade, more than doubling to 172,500 in July from 70,300 at the start of 2010.
Long-term losers: Many labor-intensive sectors are victims of shifts to lower-cost overseas production, in particular following China’s entrance into the World Trade Organization in 2001.
One of the hardest hit was the textile industry. Between 1995 and 2009, it lost 67% of its positions, then settled into a slower, steady descent. Between 2010 and 2016, jobs dropped 4%, and another 1.6% since. In the last decade, textile-mill employment has seen only two years of growth, both about 1% or less.
Apparel manufacturing is another labor-intensive sector that has never recovered from overseas competition, losing jobs every year this decade—as it has since the early 1990s.
Other sectors have been hit by technological change. Paper and paper-product manufacturing saw steep losses starting in the 1990s as personal correspondence and office work moved online. From 2010 through the end of 2016, jobs fell 7.2%. Since 2017, the sector is up less than 1%, driven by cardboard box production—think online shipping.
Oil and gas: U.S. manufacturing employment has become closely tied to oil activity, given the emergence of the U.S. as a leading oil producer—another phenomenon that predates Mr. Trump. Oil production, which is capital intensive, spurs demand for manufactured products such as steel pipes, pumps and compressors.