Good to have you on board, albeit only for part of solution to the problem, and good to see there's at least some consensus as to the diagnosis.
This doesn't mean business or corporations are 'untouchable', any more than the first amendment makes religions untouchable. They still have to abide by the same laws as the rest of us. But it does mean that government must be prohibited from legislating to promote, or persecute, economic "interests". It means government can't use the power of law to manipulate our economic decisions, regardless of the role we play (consumer, employee, manufacturer, employer, etc...).
What's wrong with, say, enforcing higher mileage for cars? Standards for consumer credit? Requiring producers that their product does not endanger the health of consumers? Limiting toxic or otherwise damaging exhaust or waste water? Safeguarding the nation's aquifers? Regulating the information on consumers corporations can store and use? All designed to "manipulate our economic decisions" in one way or another, and I find no sound reason to dismiss either of the examples.
These are excellent examples and will prompt us to get into more detail about what I'm talking about. First of all, let me say that I have no qualms with the necessary role of government in protecting the commons - those resources we agree to hold as common public property (the atmosphere, the aquifer, etc...). Laws that prohibit excessive pollution, or abuse of those common resources aren't what I would consider economic regulations. These kinds of laws are not mandating our personal decisions other than to prohibit abuse of public property. The first few examples, however, do fall under the kind of legislation I'd like to prohibit at a constitutional level. And the last one is something I honestly haven't given a lot of thought to. It's definitely something we need to work out.
"What's wrong with, say, enforcing higher mileage for cars? Standards for consumer credit? Requiring producers [to ensure] that their product does not endanger the health of consumers?"
These are really good examples of the kind of thing I'm talking about because, as you point out, they
seem innocuous - even beneficial. But they're corrosive nonetheless, and not merely because of the precedent they set (I'll try to avoid the slippery slope argument here, though I do think it's plenty valid). My first, and perhaps more predictable, objection to these kinds of laws is based on the violation of the basic right of individuals to decide for themselves how they want to spend their money, indeed, how they want to live their lives. This gets into the question of when government, even if its representing the democratic will of the people, should have the power to dictate our personal decisions.
The nature of law is to force conformity of behavior. I don't believe such power is justified unless diversity is truly intolerable. Often that's the case. We don't want people, as a rule, deciding for themselves if murder is ok, and relying on civil suits to penalizing wrongful death. The consequences are too great (death is permanent), and the circumstances where killing someone
might be justified are too rare. So we force conformity and prohibit all killing, leaving it to the courts to deal with the exceptions. Mandating conformity can make sense in other cases as well, when consensus is nearly universal, and the sacrifice of liberty is minimal - basic traffic laws, for example. But in general, I don't think we should indulge this kind of power merely for the convenience of the majority. And that's what I see going on in these three examples.
If most of us want higher mileage cars, we can 'vote' with our dollars simply by buying higher mileage cars. If we don't want to do business with creditors who don't adhere to our preferred standards, we can make that choice without forcing those standards on others. Likewise, if we don't want to use products that are dangerous, we can avoid that as well - without prohibiting that choice to others who might be comfortable with the risks. The government's role in these case should be limited to preventing fraud and ensuring transparency. As long as people are dealing with each other honestly, and not misrepresenting what is offered for trade, the government has no business interfering in our personal decisions in this way.
My second objection to these kinds of regulations addresses our agreed upon concern with business interests colluding with government. The ability to 'steer' society from a centralized authority is overwhelmingly tempting to the greedy and ambitious. I assume you envision some way to ensure that such power is only ever used for "good", but (setting aside the subjective nature of "good", which probably falls more under my first objection) even the best of intentions will involve unintended consequences. And special interest groups, most notably businesses and trade organizations, will do everything they can to ensure that those "unintended consequences" work in their favor. When controlling the implementation of regulation can mean billions of dollars in profit and loss, there's simply no way the general welfare of voters can compete.
If an automobile manufacturer can avoid expensive retooling by keeping mileage standards in line with their current models, you can bet they'll pursue such an end vigorously. Likewise, if bumping them up a little will hamper a competitor, they'll push for that. The problem with this dynamic isn't just that it encourages lobbying, but that it sets up our government as a 'deal maker', a broker that parses out favors to those who 'play ball', and takes them away from those who don't. That is the essence of corporatism.
In addition, because these kinds of regulations need to be flexible and often involve intensive detail, they're not usually created by elected legislators, but by appointed bureaucrats. These bureaucrats have even less incentive to respect the general welfare, and are that much more likely to be responsive to the desires of business and organized interest groups. Often they're even active members of the markets they're asked to regulate, creating obvious conflict of interest. The point I'm circling here is that this kind of regulatory control over society is inevitably the target of those who wish to control us. Their goals for society will only overlap with the good of society to the extent necessary to mollify voters.