There are many court cases which have protected corporations as though they were natural human beings. The following are three examples.
The first example is First National Bank of Boston v Bellotti, 1978. In this case, the court found that political donations by corporations are protected by the first amendment of the Constitution, which guarantees "people" free speech. It claimed, in essence, that money is speech. Obviously, some "people" are able to speak louder than others.
Two court cases protected corporations based upon their "rights" as stated in the fourth amendment to the Constitution.
In 1906, the court case Hale v Henkel decided in favor of corporations not having to present documentation showing whether they are or are not violating US Antitrust Laws.