The Jones Act

The Jones Act of 1920 is a law which requires that all goods transported by water between US ports be carried on US-flag ships, built in the United States, owned by U.S. citizens, and crewed by U.S. citizens

The Jones Act has the dubious distinction of harming the environment and the economy. It is detrimental to its goals of protecting US shipping, jobs and the helping the military. It is especially brutal on Puerto Rico, Hawaii and Alaska, whose economies rely on shipping. But it is protected by a coterie of companies and unions and their political benefactors. It’s the classic case of a focused special interest blood sucking money from a largely unaware public.

You can get a great intro to the Jones Act here:

General Articles
Damage to Puerto Rico, Hawaii and Alaska
Damage to the Environment
Does the Jones Act help military preparedness?
Does the Jones Act protect US jobs and shipping?
Who supports the Jones Act?