With Labor Day here, now seems as good a time as any to revisit a constant tension: how to protect infrastructure jobs without restricting innovation.

Last week, the American Association of Port Authorities invited a handful of journalists to tour the Port of Virginia, including the recently built and highly automated APM Terminal there.

The automation has allowed the port to optimize its operations, with giant machines rearranging cargo throughout the night so it can quickly and efficiently be loaded onto ships the next day. Ports in Canada and Mexico have pursued similar automation, port officials said. A failure to adapt amounts to surrendering business to the competition.

But the innovation leaves some workers behind: with the technology in place, the terminal operates with about half of the workforce it would otherwise need, they said.

"We were very careful to include the [International Longshoremen's Association]," one official said. "Many of the workers who were displaced, do eventually get retrained."

Still, the operation underscores a tension for all modes of infrastructure. Advancement can have a positive effect over the long-term, but what can be done for workers in the short-term? Can policies help to ease the pain and transition workers to new jobs without holding companies back? Are there any models for protecting and fostering both jobs and innovation?