1. Often disguised as a democracy or a constitutional monarchy, a corpocracy is when a country is run by big business, either
a. Indirectly (a common occurrence). Usually the result of pandemic corruption or gradual erosion of a nation's checks and balances on the executive branch of government; to the point where greed takes precedence over your representative's morals.
or
b. Directly (currently theoretical). There are few companies with the capital to afford starting their own direct corpocracy.
1a. I highly doubt that Congress would willingly label America a corpocracy, but honesty isn't exactly their strong point.
1b. Microsoft has enough money to buy a small country, thus forming the first direct corpocracy.
2. America became a corpocracy when both the Republicans and the Democrats dropped all pretence at serving the nation's best interests; opting to take bribes from the defence industry, large oil companies, and Hollywood instead.
While by law the U.S. is a republic, the government is actually a Corpocracy - democracy by the corporations. Corporations vote by paying politicians and political parties to put forward their agenda. The term is also endearing because of the similarity to the word "Hipocrisy".