The Declaration of Independence says:
[W]henever any Form of Government becomes destructive of these ends [i.e., the securing of unalienable rights], it is the Right of the People to alter or to abolish it, and to institute new Government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their Safety and Happiness.
When it comes time to do that, I hope that whoever has the charge of doing it will remember this lesson: separation of powers is not enough to guarantee liberty. What guarantees a space for liberty is not merely the separation of power, but a tension between the powers.
Consider, for example,
AT&T's spying on the American people. "Hemisphere is a secretive program run by AT&T that searches trillions of call records and analyzes cellular data to determine where a target is located, with whom he speaks, and potentially why."
There is a clear separation of powers between AT&T and the police. If you contract with AT&T, it has a certain power over your life because it gains access to a lot of information about you. Still, AT&T has no police powers.
The police, meanwhile, have no right to demand access to AT&T's proprietary information without a warrant.
Does this protect you? No, it does not: AT&T is happy to provide the police with everything it knows, secretly, in return for a cash payment (one that you are contributing to yourself as a taxpayer).
If the government were to nationalize the telecoms, it would lose access to this kind of spying. A nationalized telecom would have to justify its spying by warrant. By outsourcing this spying to a non-government agency, the government actually increases its powers.
So too with the "death panels," below. A nationalized single payer system would presumably have to respect the claim that you could not be denied life (or liberty or property) without due process. It might not be much better -- the VA's system simply delays the due process so long that you die anyway -- but the corporate/government alignment provides them with immediate access to a power that they could never get through Congress.
For now, the hope lies in an intensification of the tension between the states and the Federal government. There, where the powers have competing interests, there is a chance that some space for liberty will come to be between them. Tension between powers is the thing that really works.
Merely separating the powers, without a competitive tension between the powers, aggregates them just as certainly as a failure to separate them at all. Indeed, in these two examples of corporate/government collusion, the power of the state increases beyond what it could ever legitimately do should it seize the private body and run it as a formal arm of the state.