I've got to read up more on the D-1, I think it just applies to the owners of the vessels themselves.
Whatever, the arrangement is, it certainly affects the total number of union members. But, as that law guide points out, the crewmembers have to honor a strike, so it doesn't affect the union's power.
Because of the increase in intl trade, all the ports are busy. But the west coast ports are the busiest. There, you would say that they are reaching capacity, plus the union has opposed futher automation to enhance capacity. Recall the strike a couple of years ago.
There are already containers entering Canada and Mexico which then enter the US. These are not getting the scrutiny that containers arriving at our domestic ports recieve. The number of these "trans-shipped" containers will be increasing.
Note the recent anouncement of the port expansion(don't recall the name) in Mexico. Also, Burlington Northern-Santa Fe bought that leg of the Mexican rail line from that port to Laredo, TX, which gives them control all the way to Kansas City. Add to this the announced creation of an inland port in KC. With this arrangement, KC functions just like a seaport, except it is in the geographical center of the nation.
To get a better control of the security needed for the increasing number of containers entering via Canada and Mexico, we have North American Perimeter Security, which will give the US the authority to control security on these containers(and people).
If you will recall, Mexico has agreed to Perimeter Security and they have agreed to cross-border enforcement in the War on Drugs and the War on Illegals, but they have stipulated that the US Congress must enact comprehensive immigration reform.
And if you go back and look at the "get tuff on illegals" bill passed by the House in Dec, you will notice that the bill authorizes Sec Chertoff to begin implementation of cross-border enforcement, implying that comprehensive reform will be part of the package.
The fix is in.