Just for clarification--may we assume you are talking about the United States Constitution?

As point of clarification, are you repeating the thesis of Zinn in his People's History of the United States?

While his work (like James Loewen's) is important in its opposition to how history is usually tought, you should try to keep in mind the Marxist lens that Zinn always applies to history, and will shoehorn facts into his vision even when there's no reasonable way to do so. (Someone poor burns down a mansion? Clearly it is class struggle in action! Even though they are explicitly there for other reasons.)

So while there are certainly some valid points that Zinn makes about the American Revolution and American elites gaining from it (notably in relation to the Ohio territory), it should be balanced against the actual writings of people like Madison, that give a great deal of insight into the thought processes behind the creation of the Constitution, and do not show the sort of casual disregard for the general populace that Zinn intimates is there. Jefferson, likewise, shows a high regard for what we'd call the middle class.

There are countless examples of states around the globe where the government benefits only the rich and powerful, but America (pithy catchphrases aside) has not and is not one of them.