Sure, but the shareholders could always just appoint another patsy to be head of the corp. In theory, it should be the shareholders who have final responsibility as they have the power to remove/appoint all the people who make the decisions for a corporation.
The solution to that legal conundrum is easy - when a corporation is charged with a crime, whoever was in charge of the company at the time it was committed is responsible. That's how the law already works, in the rare cases that a specific person is charged at all, when the prosecution decides that a specific person is to blame instead of the company as a whole.
Anyway, for further information on the rights of corporate speech, just Google the phrase "Citizens United" and you'll learn more than you ever wanted to. It was a Supreme Court decision about two years ago, wherein it was ruled that spending money to advertise for political campaigns, as long as the candidate being spent for does not directly interact with the spender, is free speech and cannot be limited in any way or dollar amount. And by the way, corporations are people.
I elaborated on it a bit back when it was handed down, but I didn't really know what to think about it at the time. It was essentially an expansion of a prior ruling,
Buckley v Valeo, which first established the "money equals speech" idea.
That was ten months before the 2010 Congressional elections, which wound up shattering all prior records of "non-affiliated" campaign spending. Stephen Colbert has since been running a very informative series describing the founding of his "Colbert SuperPAC", a new legal construction just formed since the decision. Basically, a Political Action Committee is a specific type of federally corporation that exists to spend money on political campaigning. "Super" PACs (they're actually called that in law) can take unlimited money from other corporations in addition to individuals, never have disclose the identity of their donors, and don't have to disclose the dollar amounts or how its spent until six months after the election they spend money in. All it takes for a PAC to be a Super PAC is a one page letter of intent to the Federal Election Commission.
And if you honestly think that the FEC even can or wants to enforce ideas like "non-affiliation", feel free to Google the galaxy of PACs that formed around Sarah Palin a year ago, or the ones buying all of Herman Cain's books now.
There are a smattering of "citizens groups" campaigning for a new Constitutional amendment to reverse all this stuff.
These are the ones that get the most press, and I can already see problems with them. It requires a fairly careful legal hash to make sure no rights are denied to legit people without extending them to the wrong kind of non-people. The first line about "living human beings" for example necessarily excludes constitutional protection a dead person's estate or endangered species laws. More importantly of course, it's really hard to amend the Constitution, and by definition, all the money in the world would be lined up against such a campaign.