Today's New York Times article on political activity by the U.S. Chamber of Commerce is getting a lot of attention. And rightly so.

The article, by Eric Lipton, Mike McItire and Don Van Natta, Jr., documents massive contributions by corporations to the Chamber's political operations--$2 million from Prudential Financial, to underwrite a campaign against tough Wall Street regulation; $1.7 million from Dow Chemical, in order to fight stronger safety standards at chemical plants; and $8 million from a group of companies to support a Chamber-affiliated foundation that produces material critical of spending and regulation.

But it's only because these journalists were able to piece together evidence from incomplete, scattered tax records that we're hearing about these donations. As the Times story notes, the Chamber isn't required to disclose the name of companies financing its political activity and it has fought hard to maintain that right to secrecy.

And why are these donors so interested in avoiding disclosure? Bruce Josten, the Chamber's chief lobbyist, offers an explanation:

“The major supporters of us in health care last year were confronted with protests at their corporate headquarters, protests and harassment at the C.E.O.’s homes,” said R. Bruce Josten, the chief lobbyist at the chamber, whose office looks out on the White House. “You are wondering why companies want some protection. It is pretty clear.”

Yes, very clear indeed. Corporations are afraid that if people find out about their political activities, activists might stage protests while consumers might stop buying their goods and services. In other words, people might exercise their rights to free speech in ways that hurt the companies' bottom line. As Matt Yglesias put it, that's precisely the reason why disclosure is so important.

By the way, if you really want to get a sense of the Chamber, how it operates, and its place in American politics, I highly recommend James Verini's article from the July/August issue of the Washington Monthly