Factories can come back to the U.S. Jobs, not so much.

Ever since manufacturing employment started to decline in the U.S. after hitting a peak of 19.6 million jobs in 1979, every president has trumpeted a plan to revive the country’s industrial base. Despite these efforts, the number of factory jobs hit a bottom in 2010 (not counting a sharp one-month dip during the pandemic) and has been stuck between 12 million and 13 million for more than a decade.

The latest effort to pump up domestic output has been the most aggressive by far. Under President Donald Trump, the government has taken equity stakes in companies and browbeat industry leaders — domestic and foreign — to invest more in the US. His biggest club has been tariffs, which Trump expects will compel companies to open factories in the U.S. instead of paying duties. Even with the Supreme Court blocking Trump’s use of the International Emergency Economic Powers Act to impose tariffs, they aren’t going away.

There’s also a different sense of urgency with this latest manufacturing push. The pandemic served as an urgent wake-up call that the U.S. doesn’t make nearly enough essential goods, such as pharmaceuticals and computer chips, and that the country depends too heavily on China. A second moment of clarity for the need to regain control of supply chains came in February 2022 after China gave support to Russia’s invasion of Ukraine.“The reality is and the big picture is that reindustrialization is our future. Our trade relationships are at the heart of that," Michelle Giuda, the chief executive officer of the Krach Institute for Tech Diplomacy at Purdue University, said in a Bloomberg TV interview after the Supreme Court struck down most of Trump’s tariffs recently. "There’s no bringing the train back into the station."

Success, however, will not be measured by a gain in factory jobs. If the effort to recapture production in the U.S. is successful, it will be thanks to automation and robots, not in spite of this technology. The machines hold promise to drive down labor costs to a point where it doesn’t make sense to produce overseas and export back to the US.

The push for more U.S. manufacturing is an overdue realization that the country’s economy is vulnerable to trade disruptions that cut off vital supplies. That concern was hammered home last year when China responded to Trump’s tariffs by threatening to cut off the flow of rare earth elements, which could shut down production of a wide range of products, from automobiles to electronics.

The next conflict that impacts trade could be more permanent and damaging, which gives a sense of urgency to reinforcing supply chains. In contrast to the decades of policies to promote global trade, this national security rationale for boosting domestic manufacturing is a new and powerful argument that should garner bipartisan support for reshoring factory operations.

There’s a green angle as well that follows the same logic as farm-to-table restaurants. Locally sourced goods and parts save all the time, cost and energy of shipping goods halfway around the world. Unfortunately, it lacks the one component that most politicians focus on: job creation. Even if production returns, it will require fewer workers, though they will be better paid.

The challenges to rebuild the U.S. manufacturing base are vast. It will take time to create clusters of suppliers to support local production. Companies often struggle to hire skilled workers. The clampdown on immigration could tighten the labor market to the point that it slows growth. Also, robots are expensive, require programming and need maintenance. This makes it difficult for small businesses to adopt automation.

Still, the use cases for robotics have been ballooning as the machines become more dexterous. Cameras and sensors allow robots to see and distinguish objects. Machine learning has made them more capable and easier to program. Mobility is the latest breakthrough and autonomous mobile robots — the squatty machines that can carry pallets, racks and bins — are now common in warehouses. The holy grail for automation is a general-purpose robot that can do multiple tasks with simple instructions. This is the promise that AI brings to robotics, and specifically to humanoid robots — whether on legs or wheels.

Humans will be alleviated from the most tedious, physically stressful work and instead tend to the machines. This has happened throughout history — always despite hand-wringing about the potential of massive unemployment. The productivity gains from machines have allowed people to earn more, enjoy more free time and avoid the repetitive or backbreaking tasks that damaged their health.

After many false starts on reviving U.S. manufacturing, the effort is now driven by the powerful forces of national security and the widespread recognition that the U.S. has become too dependent on its main adversary for essential goods. There’s a real possibility that tariffs will outlast the Trump administration but perhaps applied in a less chaotic manner. If a manufacturing rebound doesn’t take place under these conditions, it’s hard to see how it ever will. Regardless, don’t expect a boom of manufacturing jobs.

This column reflects the personal views of the author and does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners. Thomas Black is a Bloomberg Opinion columnist writing about the industrial and transportation sectors. He was previously a Bloomberg News reporter covering logistics, manufacturing and private aviation.