Thoughts on a Legitimate Corporatocracy

Corporation - a body formed and authorized by law to act as a single person although constituted by one or more persons and legally endowed with various rights and duties including the capacity of succession

Merriam-Webster's Collegiate Dictionary 11th Edition

Corporations are legally a single person which are required to "live" (i.e. have an office or headquarters) in a specific location or state. So why don't they have the right to vote?

Now, I know that's a radical concept, but hear me out. Right now, corporations are allowed to lobby only. This can lead to bribes or their more legal but still morally reprehensible cousins. There are different ways to deal with lobbyists, Britain does not allow political television ads, which greatly cuts down the need to campaign contributions, which cuts down the effectiveness of lobbyists. But, since corporations are already a legal entity, why not give them the right to vote? Or their own house in Congress?

Corporations are simply social and legal constructs, very similar to a state, province, or nation. They are motivated by profit to provide goods and services that benefit us, the public. Why do they not have a say in issues that affect them?

I'm not a lawyer or a politician, and I don't pretend to be familiar with every repercussion this could have, I'm simply throwing the idea out there for discussion. What do you think?