Rights retained by the people, and powers that are retained by the states or the people are different than those that the "United States", meaning the Federal government, has the authority to utilize.
That authority is only obtained through the Constitution and the people have already indicated (through the original ratification process)that the only way to add to it is through the amendment process. Without an amendment, the people, through their federal representatives, are poweless to bequeath new powers to the Federal beheamouth.
So, the only way for the people, through their representatives to extend those rights, powers and priveleges to the United States is to do so through the amednment process of the Constitution. Any attempt to do it otherwise is illegal, null and void as far as law and theory go.
Reality says that since they are willing to enforce unconstitutional acts at the point of the sword/gun...that they have become the defacto law anyway, at least up until the point that the natural rights as spelled out in the Declaration of Independence come into play.
It looks like the underlying premise of your reasoning is that the people have no retained right to have their representatives act on their behalf to accomplish whatever the people themselves have the reserved power to accomplish. The opposite of that is an underlying premise of my reasoning and I did not see anything in your reasoning to cause me to accept your premise over mine.
If my premise is correct, and the people have the Constitutionally retained right I stated and exercise that right, then seems to me that amounts to Constitutional authorization.
And this is the (probably unintended) consequence of an amendment to the Constitution. But just because consequences are unintended doesn't mean they don't exist.
Note that lower down in the Declaration of Independence it says that Governments derive their just powers from the consent of the governed, which relates to what I tried to lay out. Still further down are complaints about what the Government or the King did that the people did not want done, but there are also complaints about what the Government or the King did not do that the people did want done.
By the way, I don't very much like the implications of my reasoning, though that's irrelevant.