Could the Supreme Court declare a amendment proposal unconstitutional?

Not quite. I think it’s unlikely the court will ever invalidate an amendment/proposed amendment because of its substance, because my opinion is that the only valid challenge to substance is the Senate entrenchment clause and I think such an amendment is unlikely to be proposed.

As for ruling on the substance of amendment proposals prior to ratification, if a State is not harmed by the proposal itself I doubt whether it could even reach the Court.

Cannot rule an amendment proposal unconstitutional because of its substance, with the single exception I mentioned. I have no qualms with the Court upholding a proposal when challenged on the basis of its substance - with the one exception.

No, it is my opinion.

~Max

One academic argued that constitutional amendments should be considered unconstitutional only if they violate core democratic norms (where I’d argue Article V Senate protection language does not apply) and that these norms must be transnational (ditto).

I’m not claiming that this would fly in the US (where Article V would trounce transnational democratic norms, as would any other aspect of US law as interpreted by the current judicial regime), but I thought it warranted mention.

Hollingsworth v. Virginia

Would it necessarily have to though?*

Let’s propose an amendment that says that states with a population under say 1m people at a given Census only get 1 Senator. And states with over 30m get a third Senator. Right now that would cost SD, ND, and WY a Senator each and add 1 to CA and TX. These to be reevaluated following each decennial census.

As long as the enacting clause said “this amendment shall not take effect unless ratified specifically by SD, ND, WY, CA, and TX as well as the remaining number of requisite States”, why would this run afoul of Article V? Based on this, they gave their Consent.

* I agree that, in reality, there is no way on this earth that SD, ND, and WY would ever agree to such nonsense. CA and TX would agree in 90 seconds flat. FL would argue that it should be 20m.

Because every state that is not CA & TX has been denied equal representation in the Senate with those states. I don’t think there’s any way you’d get all the other 48 states to agree.

Fair enough, so drop that clause. Just remove Senators from very small states, no addsies.

One could argue that there is precedent for states consenting to the loss of Senate representation: During the Civil War, the treasonous states didn’t send delegates to the Senate.

I would speculate the process you describe wouldn’t work. Because the text says “equal suffrage” not “equal or greater suffrage”.

So while in your hypothetical North Dakota, South Dakota, and Wyoming agree to have unequal suffrage (one Senator instead of the two the other forty-seven states get) the other forty-seven states now also have unequal suffrage (two Senators instead of the one North Dakota, South Dakota, and Wyoming get) and those other forty-eight states never consented to that.

Granted, this would require some state to officially complain that it was receiving more Senate representation than some other states. But legally they would have a case if they did so.