From its *waters*????? From its ports...maybe,but what harm can come from a ship sailing from Seattle to Anchorage without a stop in Canada? Absolutely disgusting!
No harm at all. The only problem there is that the Jones Act has a bunch of very onerous and expensive requirements for all domestic maritime travel between U.S. ports. Any ship making this trip must be U.S.-made, U.S.-flagged, and operated by a U.S. crew.
This is why it's cheaper to transport cargo between Los Angeles and Singapore than between Los Angeles and Honolulu ... even though the ship traveling from Los Angeles to Singapore sails past Hawaii on its voyage.