The law considers a corporation to be a "person"

On August 1st Democracy Unlimited filed a brief in the U.S. Supreme Court challenging “corporate personhood,” the illegitimate and undemocratic legal doctrine which allows courts to overturn democratically elected laws that attempt to control corporate harm and abuse...

“The notion that corporations have the same speech rights as people under our Bill of Rights is contrary to the words, history, spirit and intent of our Constitution,” said Clements. “The organizations that joined to bring these arguments to the Court have worked with others for many years to empower democratic self-government. They remind us that corporations do not vote, speak, or act as people do, but are products of government policy to achieve economic and charitable ends. As such, corporations need not be allowed to influence our elections if Congress and State governments judge that such influence is detrimental to democracy.”

The Supreme Court is considering overturning federal campaign regulations for corporations, originally enacted in 1907, and may soon overrule previous Supreme Court decisions that have upheld the Constitutionality of legislative restrictions on corporate money in politics...

The brief filed by Democracy Unlimited argues that corporations are legal entities created by state or federal law for economic, charitable or other purposes, and were never intended to be included within the Constitution’s Bill of Rights...

More details and a long discussion thread at Reddit.

The Supreme Court will be hearing the case in September. Expect to hear more about this then, but you can get a head start now.