This article is from the Copyright Law FAQ, by Terry Carroll with numerous contributions by others.
Yes. The United States has expressly waived its immunity to suit for
copyright infringement. 28 U.S.C. 1498.
For some time, it was unclear whether the Eleventh Amendment of the U.S.
Constitution operated to make a state immune from suit for copyright
infringement. In BV Engineering v. University of California at Los
Angeles, 858 F.2d 1394 (9th Cir., 1988), UCLA successfully defended a
copyright infringement suit on the ground that it had such immunity.
Although UCLA won that suit, Congress responded by passing the Copyright
Remedy Clarification Act, PL 101-553, in 1990. This law added section
511 to the Copyright Act, which had the effect of removing the immunity
defense. It became effective June 1, 1991.
Today the law is very clear: the United States government and the
governments of each state may be sued for copyright infringement, and may
not plead immunity as a defense.