Can you cite legislation or instances wherein exhibits were cancelled/censored?

Last year, the case of the MECA show in Oakland, “A Child’s view of Gaza” was cancelled: http://electronicintifada.net/content/gaza-childrens-images-war-censored-under-pressure-us-israel-lobby/10373

there are many angles to this: the fact that children would be viewing it, museums self-censorship, and Israel lobby—for a balanced viewpoint….

precedence and legislative references much appreciated.