I know that Communists are OK, but I cannot recall whether socializing all wealth, would be legal if the majority of citizens agreed on it.
Anything is legally possible, if it is done constitutionally - meaning, if a constitutional amendment is required to implement your constitutional revolution, then you make the necessary constitutional amendment. In short, if communists take power by constitutional means and enact their programme by constitutional means (including any necessary constitutional amendments), that’s not illegal, no matter how much it revolutionises the American social and economic order.
However there is a sense of “revolution” which implies a disruption or supplanting of the existing constitutional order by some supervening act (not necessarily a violent act) which supplants it and establishes a new constitutional order. Such a revolution is inherently illegal from the perspective of the preceding constitutional order. If you envisage a constitutional revolution of this kind then, naturally, no, it won’t be legal. If you mean “revolution” in this sense then the implementation of a communist programme by constitutional means is, by definition, not a constitutional revolution.
Legal, probably. If the majority of citizens agreed to it, they can probably vote for enough like-minded politicians to change the law to let them do whatever they want.
Moral, no.
Retroactively? Absolutely. All revolutions are based on retroactive legitimization.
One doesn’t need to change the Constitution nor even most law to create a Communist State. All you would need to do is mandate that everyone have the same salary. Congress could easily do that tomorrow.
But would it be two thirds, then?
Day after tomorrrow - 90% of the country goes freelance.
This. It’s a revolution.
You think what the founders did was legal?
There is more to communism than that. The state would have to appropriate the means of production. That would be a “taking”. Not constitutional.
But if everyone wanted it, we could change the constitution.
Because of the mechanism of democracy and because legislators belong to the third of population, who don’t need/want sosializing, change is well - maybe legal, but practically imposible. What would the result be after a referendum?
Political revolutions are always illegal by definition. That does not mean revolutions are always wrong or never worth having, but it does mean that the stability of the rule of law is something you are at least temporarily giving up in the process – and there are all kinds of things that can go wrong when there is no settled law in force.
Referendum? Who said anything about a referendum? The US constitution is not amended by referendum.
A brand new constitution endorsed by referendum and entering into force on the back of that endorsement would indeed be revolutionary, in the legal sense, even if there were no violence involved.
But, unlikely though it may be in practice, if an amendment or a series of amendments, passed in the prescribed fashion, were to alter the US constitution so as to vest the ownership of the means of production in the state, as the agent of the proletariat, and to make various other changes and introduce various other measures (which need not include equal pay for everybody, incidentally), we might say that that that was revolutionary in the political sense, but legally it would not be a revolution. It would just be an exercise of the constitutional power of amendment, as has been done many times before.
I don’t understand what you mean by “legislators belong to the third of population”, but I was not commenting on the practicality or likelihood of this happening. But yes, it is, for all intents and purposes, impossible in the US. Something would have to radically change the environment to make it practical.
Within the current constitution, there’s nothing (as far as I know) stopping the state from acquiring property by lawful means. In theory, the state could acquire most means of production (actually easier as you shift to a mainly service economy).
From there, the government employee and subcontractor mass just continues to grow, until everyone is effectively employeed by the government. You wouldn’t need to ban free enterprise, just repeal any legislation requiring open competition, and grind the free enterprise into the ground with your state machine.
Legal communism without even changing the constitution.
There is so much in-built conservatism in a representative democracy. “Period of stagnation” may some day refer to the political institutions of the U.S.
While a series of amendments would do it, there is also significant precedent for a Constitutional Convention. The latter would presumably override any existing law and government by establishing representation a substantial majority of citizens.
True, and I was wrong when I said, above, that it would violate the “takings clause”. The courts have not limited the scope of the government’s power to claim private property for public use.
However, there is the practical matter of just compensation. Does the US treasury have enough $$ to acquire all the private property in the country? OTOH, if they did so, it would soon become almost worthless, so maybe it wouldn’t cost that much after all. 
O rly? I don’t remember anyone saying why the government couldn’t nationalize GM, just that they hadn’t.
Under Eminent Domain, if nothing else, the government has full right to seize whatever it wants, so long as it serves the interests of the public. It must offer compensation, but the government can simply raise taxes as needed.
Justifying a takeover of GM under eminent domain would be a stretch, to say the least.
I didn’t say that eminent domain would have been used. I said that eminent domain could be stretched for the purpose, but so far as I was aware ED isn’t even necessary for the government to nationalize a business. They can just do it.