The next territorial boundary marks the State's potential contiguous zone, which extends 24 miles
offshore. Within this zone, a coastal state can stop and inspect vessels and act to punish (or prevent) violations of its laws within its territory or territorial waters. The contiguous zone solves a vexing problem. As Malcolm Evans describes it:
Traditionally, where the territorial sea ends, the high seas began and the laws of the coastal State no longer apply. However, policing maritime zones is no easy matter and, unlike land boundaries, they are simple to cross. It would therefore be easy for vessels to commit offences within the territorial sea but to evade arrest by moving just a little further seaward. The answer is to permit coastal States to arrest vessels outside their territorial seas in connection with offences that either have been committed or which it is suspected are going to be committed within their territorial sea.
In 1999 President Clinton extended the U.S.'s contiguous zone from 12 to 24 miles.
The potential territorial sea extends 12 miles off the coast. Here the State has territorial jurisdiction, but only up to a point--the right of innocent passage still applies. The LOSC says:
1. The criminal jurisdiction of the coastal State should not be exercised on board a foreign ship passing through the territorial sea to arrest any person or to conduct any investigation in connection with any crime committed on board the ship during its passage, save only in the following cases:
(a) if the consequences of the crime extend to the coastal State;
(b) if the crime is of a kind to disturb the peace of the country or the good order of the territorial sea;
(c) if the assistance of the local authorities has been requested by the master of the ship or by a diplomatic agent or consular officer of the flag State; or