You have probably heard by now that for the first time in nearly half a century, the International Longshoremen’s Association is on strike.

Some 45,000 rank and file members have walked out at 36 ports across the Eastern Seaboard and Gulf Coast, from Boston to Baltimore to New Orleans.

So shipping containers stocked with everything from cars to Christmas toys are now in logistics limbo — as is kind of the rest of the U.S. economy, not to put too fine a point on it.

The longshoremen want higher pay; reportedly a raise of more than 60% over several years.

But there’s a sticking point between labor and management that’s arguably a bigger deal: Automation.

Dockworkers want language in their next contract that protects them from the robots and software and now AI that threaten to do a lot of their jobs, from moving and stacking containers to checking in the trucks that take those containers away.

Outside the Port of Baltimore, about 80 members of the International Longshoremen’s Association were picketing in the rain today.

Some ports on the Eastern Seaboard are what’s known in the shipping industry as semi-automated.

“That means that a longshore worker will still move the container from the ship to the backland, the storage area,” explained Geraldine Knatz, the former director of the Port of Los Angeles.

But for some ports on the West Coast and a growing number of ports in Europe and East Asia, an autonomous machine does all of that, no human required.

“This is one sector where we are woefully inefficient, we’ve resisted essentially as many efforts at automation as possible in comparison to our peers in China or in Europe,” said Jason Miller, a supply chain professor at Michigan State.

Miller says the U.S. consumer bears the cost of that inefficiency in the form of higher import prices.

Port operators have typically tried to reassure longshoremen that they can be reassigned to a different role once the robots arrive, says Jim Kruse at the Texas A&M Transportation Institute.

But that’s easier said than done.

“You can say, ‘Well, they can just learn how to maintain and fix automated equipment.’ But you can’t just walk over and do that, you have to be trained to do that, you have to know how to do those things,” said Kruse.

Kruse says ports will have to figure out some way to be more efficient; he’s seen forecasts of seaport trade volume doubling by 2050. At the same time, they’re also under pressure to emit fewer greenhouse gases.

“One way to electrify your operation is to go fully automation, so that’s another driver,” said Knatz.

One that may be in conflict with keeping longshoremen working.