II. HETEROGENEITY
In the United States, the copyright system is directed principally toward the goal of incentivizing the creation of
new works. n12 To [*700] achieve that goal, it provides protection to a number of broad classes of original creative
works. n13 This system provides exclusive economic rights to authors (or their employers) of works for a period of at
least seventy years following creation. n14 Generally, the bundle of exclusive rights provided to creators of protected
works is uniform across classes of work and across creators. n15 In almost all cases, n16 the system does not provide
for separate moral rights, such as rights of attribution or integrity. n17 With the possible exception of permanently
granting a work to the public domain, n18 there is no way to choose an alternate system of protections for one's
creative works. n19 Our copyright system thus generally takes a one-size-fits-all approach.
There are some aspects of the existing copyright system that limit its homogeneity. The fair use defense provides a
backstop against the assertion of copyright under circumstances that are deemed contrary to the public interest, such as
when protection would limit free speech [*701] or downstream creativity. n20 The factors considered in the fair use