Doug Kendall’s argument in favor of tight campaign finance controls on corporations is, essentially, that corporations are too rich and powerful (and thus would have too much ability to “buy” elections), and that the freedoms listed in the Constitution and Bill of Rights are designed for individuals, not corporations:

In his historic run to the presidency, Barack Obama broke every political fundraising record, raising nearly $750 million from more than a million contributors in 2007 and 2008. Now consider a corporation such as Exxon Mobil. During 2008 alone, Exxon generated profits of $45 billion. With a diversion of even 2 percent of these profits to the political process, Exxon could have far outspent the Obama campaign and fundamentally changed the dynamic of the 2008 election.

Looking at the numbers, it’s strange that everybody’s first conclusion isn’t be that government shouldn’t be so significant to people’s lives, in a consolidated, national way, that individuals or corporations would have such mammoth incentive. Exxon Mobile, as an organization, doesn’t want to spend billions of dollars on politics, so don’t make it a monetary winner for it to do so.

The line between corporations and individuals when it comes to constitutional protections is as old as the United States. The framers wrote the Constitution to protect citizens and the people and never once used the word “corporations.”
Early Supreme Court rulings embraced this distinction, holding that the legal rights of a corporation derive from its corporate charter, not the Constitution.

The Constitution lays out the foundation for the structure of our government, which means that any laws governing corporate charters must conform with the Constitution. And the Constitution declares that Congress can pass no laws abridging free speech, and it is implicit that political speech ought to be the most protected of all. That citizens sharing a corporate structure choose to join their resources for political purposes ought to have no bearing on that fact. That they have organized themselves thus for the purpose of economic activity is irrelevant on its face.
If corporate campaign contributions are a problem, then the remedy would be to propose an amendment to the Constitution. What we’ve done, instead, as part of Kendall’s “progress,” is to create an alternate amendment process whereby the federal legislature passes a law, the federal executive signs it, and the federal judiciary stamps its approval. The consequence is ultimately that more power — and money — flows to the federal politicians, whether individually or for use in their capacity as officials.