As a matter of interpretation of the word "person" in the Fourteenth Amendment, U.S. courts have extended certain constitutional protections to corporations. Opponents of corporate personhood seek to amend the U.S. Constitution to limit these rights to those provided by state law and state constitutions.
Others argue that corporations should have the protection of the U.S. Constitution, pointing out that they are organizations of people, and that these people shouldn't be deprived of their human rights when they join with others to act collectively. In this view, treating corporations as "persons" is a convenient legal fiction that allows corporations to sue and to be sued, that provides a single entity for easier taxation and regulation, that simplified complex transactions that would otherwise involve, in the case of large corporations, thousands of people, and that protects the rights of the shareholders, including the right of association.