Neither party is likely to back the union with automation looming, as the prospect of long-term votes and cash switches to shippers. The recent layoff of 1600 UAW workers and the rapid development of self-driving vehicles certainly isn't helping. The long-term political clout of unions is eroding fast, as evidenced by Biden's recent treatment of the rail union.
I'm reminded of the Michigan (bi-partisan) protections of workers, early 1990's. Michigan restricted replacing workers with automation. You could automate a given plant to increase production, but had to have as many employees after as before, and weren't allowed to terminate; Detroit auto production was already hitting demand... so, they closed plants, built new ones with the automation, pink slipped everyone at the first plant, offered rehire to a selected few in the new plant... and in some cases moved the plant's production to another state. My aunt was working in one that was doing so.
Fighting manufacturing automation results in losing manufacturing to other locations.
But shipping's not as clear cut an option to relocate. Shipping ports are where they are because demand is there. And demand is there because access to shipping and food is there, and often, a military base or mining system.. They grow in a feedback loop. And there's the service radius issue - shipping is cheapest by ship; second is rail, third is road, fourth is air, 5th is suborbital flight (a few orders of magnitude difference for space). There's money to be made if Musk, Bezos, or Beck (or the Chinese or Indian space programs) can get reliable rapidly reusable suborbital rocketry down to merely one order of magnitude above air. Rail is usually 1/3 to 1/4 the cost of road; fast ocean is often half rail's cost, and slow ocean as low as 1/6 rail. (Slow ocean is modern container ship or small bulk sailing vessels, and they're up to about 2/3 the speed of fuel oil driven shipping. They use a variety of sailing modes - my favorite is the vertical wind turbines driving the screws, as it's only issue is the strength of the wind.)
Usibelli Coal Mine once looked at building a new water port to reduce rail costs of shipping coal via Anchorage... but the cost of creating and operating a closer port was too much initial cost to justify the swap. (plus, the locals where they wanted to put it didn't want their whaling nor fishing impeded by a commercial port, nor the influx of white-folk to staff a port.) Had they been a half-again further from Anchorage, they'd have had a break-even option...
It's important to not oversimplify the calculus of the port economics... the variables for water port economics include costs per mile for rail, road, and air (and maybe soon, suborbital rocket), the local demand, the local pricing, the local available workers, the costs of coastland, the environmental impacts, and the political impacts.. Also note: a couple of companies are hoping to disrupt the rail industry by use of dirigibles (aka zeppelins) and blimps. Solar powered dirigibles could, in theory drop below the current rate of rail. Currently, it's the handling costs of load/unload - airports generally aren't set up for airships nor standard 1-2-2.25 TEU intermodal, nor are most cargo aircraft...
I hope the strike doesn't restart in January... but I'm not optimistic about it. The needs of the workers are at odds with the good of the population in those ports and their draw zones. Automation is better for the regions served, as it reduces costs a lot.