The Amateur Radio Service

By international treaty, the Amateur Service in every country is a  licensed service. That is, a government agency has to approve the application of every ham to transmit. It allows amateurs to communicate internationally and directly, without using any kind of intermediate system that regulates their activities. Because of the power and scope of Amateur Radio, hams need a minimum amount of technical and regulatory background so they can coexist with other radio services, such as broadcasting.

By maintaining the quality of licensees, licensing helps ensure that the
Amateur Service makes the best use of its unique citizen access to the airwaves.
Amateur Service sets ham radio apart from the unlicensed services
and is recognized in the FCC rules as the Basis and Purpose of the Amateur
Radio Service, rule 97.1:

Recognition of ham radio’s exceptional capability to provide emergency
communications (rule 97.1(a))

Promote the amateur’s proven ability to advance the state of the radio
art (rule 97.1(b))

Encourage amateurs to improve their technical and communications
skills (rule 97.1(c))

Expand the number of trained operators, technicians, and electronics
experts (rule 97.1(d))

Promote the amateur’s unique ability to enhance international goodwill
(rule 97.1(e))

You can find all the rules for Amateur Radio at wireless.fcc.gov/rules.html