Manufacturing is becoming too successful for its own good. The sector is growing so fast that it cannot find enough people to fill open positions, and that shortage is threatening to hurt the nation’s economy in the coming years.

One key reason why the jobs are unfilled — 450,000, according to the Bureau of Labor Statistics, up from about 100,000 during the recession — is that many of them need people from STEM fields: science, technology, engineering, and mathematics. Congress isn’t doing much to address the shortage. One thing that could fill the need, expanding high-tech immigration, is a no-go in the current climate.