That’s it – keep drinking the Kool-Aid. The Supreme Court has NEVER decided that Congressional consent IS NOT required of the NPV compact.
First, why don’t you READ the citations you list?
United States Steel Corporation v. Multistate Tax Commission decided that the creation of the commission DID NOT assert any new powers that the states involved DID NOT already have.
Virginia v. Tennessee concerned a boundary line between the states. This case was a technical determination of the original boundary line, so as NOT to involve any interest of the United States.
Second, DO NOT “cherry-pick” your quotations.
In Virginia v. Tennessee:
“Looking at the clause in which the terms ‘compact’ or ‘agreement’ appear, it is evident that the prohibition is directed to the formation of any combination tending to the increase of political power in the states, which may encroach upon or interfere with the just supremacy of the United States.”
We now need to look further at the decision:
”The terms 'agreement' or 'compact,' taken by themselves, are sufficiently comprehensive to embrace all forms of stipulation, written or verbal, and relating to all kinds of subjects; to those to which the United States can have no possible objection or have any interest in interfering with, as well as to those which may tend to increase and build up the political influence of the contracting states, so as to encroach upon or impair the supremacy of the United States, or interfere with their rightful management of particular subjects placed under their entire control.”
Still more:
Looking at the clause in which the terms 'compact' or 'agreement' appear, it is evident that the prohibition is directed to the formation of any combination tending to the increase of political power in the states, which may encroach upon or interfere with the just supremacy of the United States. Story, in his Commentaries, (section 1403,) referring to a previous part of the same section of the constitution in which the clause in question appears, observes that its language 'may be more plausibly interpreted from the terms used, 'treaty, alliance, or confederation,' and upon the ground that the sense of each is best known by its association ('noscitur a sociis') to apply to treaties of a political character; such as treaties of alliance for purposes of peace and war, and treaties of confederation, in which the parties are leagued for mutual government, political co-operation, and the exercise of political sovereignty, and treaties of cession of sovereignty, or conferring internal political jurisdiction, or external political dependence, or general commercial privileges;' and that 'the latter clause, 'compacts and agreement,' might then very properly apply to such as regarded what might be deemed mere private rights of sovereignty; such as questions of boundary, interests in land situate in the territory of each other, and other internal regulations for the mutual comfort and convenience of states bordering on each other.' And he adds: 'In such cases the consent of congress may be properly required, in order to check any infringement of the rights of the national government; and, at the same time, a total prohibition to enter into any compact or agreement might be attended with permanent inconvenience or public mischief.”
The question [which the Supreme Court has NEVER answered] is whether a compact such as the NPV is a “political compact”, as described, above.
It may well be determined [at a future date] that it is …
Additionally, the Court may likely conclude that [vis-a-vis the Constitution] the "United States" referred to in the quote means the States - or rather, the PEOPLE of the United States.
If so, the NPV DIMINISHES the political power of states [and their citizens] that DO NOT participate in the NPV, as well as those that do, since it PREVENTS participating states from rescinding their agreement “at any time” [after the blackout date].
Because each state has independent power to award its electoral votes in the manner it sees fit, it is difficult to see what “adverse effect” might be claimed by one state from the decision of another state to award its electoral votes in a particular way. It is especially unclear what adverse “political” effect might be claimed, given that the National Popular Vote compact would treat votes cast in all 50 states and the District of Columbia equally. A vote cast in a compacting state is, in every way, equal to a vote cast in a non-compacting state. The National Popular Vote compact does not confer any advantage on states belonging to the compact as compared to non-compacting states. A vote cast in a compacting state would be, in every way, equal to a vote cast in a non-compacting state. The National Popular Vote compact certainly would not reduce the voice of voters in non-compacting states relative to the voice of voters in member states.