The nation’s two dock worker unions may take the lead in forming a maritime labor alliance to protect their jurisdiction against encroachment by non-maritime unions or non-union employers.

The presidents of the International Longshoremen’s Association on the East and Gulf coasts and the International Longshore and Warehouse Union on the West Coast have already discussed such an alliance that would presumably include other maritime unions.
ILA, ILWU Consider Alliance Against Non-Union Forces | Journal of Commerce