If a convention proposed an amendment that repealed & replaced the entirety of the Constitution, then the stipulation that "no State, without its Consent, shall be deprived of its equal suffrage in the Senate" can be gotten around, either with the new Constitution stipulating that neither the Senate in its current form nor the Article V Senate clause are repealed in the new Constitution (in which case, the new Constitution would still get to come into effect upon only 3/4ths of the states ratifying it); or with all 50 states approving the new Constitution (much easier said than done, of course, though still required if the new Constitution chooses to keep neither the Senate nor the Article V Senate clause); or legal acceptance of an argument to be made that, if the new Constitution abolished the Senate, then no state could technically have been "deprived" of its "equal suffrage" in a Senate that doesn't exist.
That may be solid grounds for legal secession.
It wouldn't be grounds for legal secession. The Supreme Court has already ruled that the only grounds for legal secession are successful revolution or consent of the states.
Is that not breach of contract? Or do individual states even exist as semi-sovereign entities?
It wouldn't be breach of contract for the simple reason that the Constitution isn't a contract. The Constitution is a law. Indeed, it proclaims itself as such, as the Supreme Law. A law isn't a contract.
Now, if the Constitution is the Supreme Law, & there's no law without a sovereign, then who's the Sovereign, the supreme lawgiver? The People? Yes, but not directly. It's the people acting through the constitutional amendment process (i.e. votes of 3/4ths or, in the rare case pertaining to the Article V Senate Clause, all 50 of the states).
Furthermore, the US isn't a society of states; rather, it's a society of people voting by state through legislatures or conventions. The subtle distinction that needs to be understood is that voting by state doesn't make it a society of states, considered as persons party to a contract. Legislatures/conventions aren't corporate persons.
Not to mention, even if the above weren't the case, two of the three scenarios that I described earlier would mean full compliance with the constitutional ratification process anyway, & the third (latter) scenario was under the condition of "legal acceptance," meaning either the Supreme Court (possibly unlikely, due to the political question doctrine) or, at the very least, the ratifying states have chosen to operate under the sincere legal belief that abolishing the Senate doesn't technically deprive a state of its "equal suffrage" in the Senate since the Senate would no longer exist.
Could a national, general plebiscite agree to abolish the current Constitution and adopt a new one?
Article XIII (or whatever) This Constitution shall supersede and nullify any previous Constitutions upon winning a 3/4 majority in an election open to all citizens of the United States, both natural born and naturalized.
I mean, this happens in other countries as a regular thing, but we've never gone through it.
No, because such an adoption of a new Constitution wouldn't be procedurally valid under the constitutional amendment process, & thus, the "new Constitution" wouldn't be valid unless & until it was successfully ratified under the procedurally valid constitutional amendment process (i.e. as it currently stands). After all, we're not France circa 1962, & our Supreme Court wouldn't rule that it falls outside of its jurisdiction to strike down a reform enacted by the American people (especially when done so in an invalid manner).
The only scenario in which the new Constitution could take effect via a national referendum would be a stipulation within the new Constitution that, upon the procedurally valid ratification of the new Constitution by the states under the current constitutional amendment process, the new Constitution would not take effect unless & until the new Constitution was approved in a referendum, & that, until such a national approval has been successfully obtained in a referendum, the previous Constitution (i.e. the current Constitution) would remain in force for the time being.
The easiest way to get around the Senate is to allow the Senate's continued existence, but allow the House to pass bills on the behalf of Congress without approval from the Senate.
Not necessarily. An argument could definitely be made that depriving the Senate of its voting power as a body amounts to depriving states of their equal suffrage (which, strictly speaking, can be interpreted as the right to vote) in the Senate.
The easiest way to get around the Senate is to allow the Senate's continued existence, but allow the House to pass bills on the behalf of Congress without approval from the Senate.
Turning the Senate into the House of Lords, with power to say "You might want to take another look at that" but without power to say no?
I'm not sure how I feel about that.
PARLIAMENTARY AMERICA WOOHOO FTW!!1!!
