It's a lot worse than the way you describe it.
The intended method for Constitutional law to work was that the powers of the Federal Government were enumerated... and all other powers reserved for the states. Unless the Constitution gave the Government the authority to do something, it couldn't be done, even if the public supported it. (And if they really supported it, there was the Amendment process).
With the reinterpretation of the Commerce Clause (and to a lessor extent the General Welfare Clause), the entire idea of Constitutional law has now been reversed. For the most part, that means unless the Constitution specifically prohibits the Government from doing something, it can now do it.
As an example, based on current precedent, there is little chance that completely socialized single payer healthcare would found be found unconstitutional.... even though the Constition clearly doesn't grant that sort of power. So through nothing greater than a simple majority vote, the federal Government could suddenly nationalize a huge chunk of the GDP.
Now you may think that's a good idea, but if a dramatic increase in federal Government power like that is possible with a simple majority vote, what else could they do that you might not like... but would no longer have the Constitution to protect you. So except in extreme cases, the "legal system" is pretty much out of the loop here.
From Justice Kagen's confirmation hearings on the Commerce Clause:
Sen. Coburn: "If I wanted to sponsor a bill and it said, ‘Americans, you have to eat three vegetables and three fruits every day,' and I got it through Congress, and it's now the law of the land, gotta do it.... Does that violate the law?"
Kagan: "Sounds like a dumb law."
Sen. Coburn: "Yeah, I got one that's real similar that I think is equally dumb." (ObamaCare)
Kagan: (Pause) "But I think the question of whether it's a dumb law is different from the question of whether it's Constitutional. And I would think courts would be wrong to strike down laws that they think are senseless just because they're senseless."
She was unwilling to say that the Commerce Clause could not be used in this manner.... how much more extreme of an example could you ask for? If the commerce clause could be used like this, then what couldn't it be used for? ( And to my horror, her position on this is actually in the current legal mainstream.)
We are to the point now of almost being a direct democracy... with the power of Government limited only by what politicians can get 50.1% of the public to support. And history shows how that usually works out.