::::::An excellent question! Personally, my line would be that SCOTUS would not be able to invalidate it....sort of. The phrase is that it'd be "valid to all Intents and Purposes, as Part of this Constitution" if done. This sort of touches on UK constitutional theories - Diceyan orthodoxy versus Jennings. My perspective would be that yes, the amendment would be invalid, providing that it was made at a point where that passage in Article V still existed. However, were congress to pass one amendment removing that condition, and another making the necessary changes....