Thank you for the correction.
There was no necessity in the Constitution for prevention of unilateral secession per se, its interdictions were throughout with the bans upon states...
This is incorrect. Remember that the Constitution was an agreement executed by the Peoples of the States directly, assembled in ratification conventions for the purpose. Thus the powers enumerated in Article I that flowed from the States to the United States are listed one by one, because they are limited delegations of the enumerated powers.
In the Confederation period, the U.S. government was basically Congress and a very limited federal establishment that answered directly to Congress. The ambassador corps, the Army and Navy, the Mint, all answered directly to Congress, which acted as agens in rebus and factotum of the States but was not superior to them. The States very clearly and without effective contradiction possessed all powers of Sovereignty, and they exercised them. The Union literally existed in the Congress -- Congress was the Union, and it prosecuted foreign policy for the States -- but it was States' powers which it wielded.
By delegating the enumerated powers to the Federal Government, the States were basically reaching for an economy of scale in government, and in order to allow these delegations to work properly, they had to recuse themselves from certain activities.
But here is the critical insight: Nobody forbade the States anything. They recused themselves, and they delegated. This was because, even as the States were considering the Constitution, they were still every bit as much the Sovereigns of their own destinies as they had been the day that George III admitted the fact in signing the Treaty of Paris.
What did not happen, is that the States abjured Sovereignty, or gave over the Sovereignty of the People to a new entity. The words do not exist in the Constitution, which is the only relevant document. To the contrary, the Ninth and Tenth Amendments make it abundantly clear that what you claim happened did not happen. The words did not come out of the People's mouths, the words did not flow from their pens. It didn't happen.
The transfers of governmental power listed seriatim in the Constitution happened, one by one. The abrogation of Sovereignty by the People did not happen.
And the People, who are they? 4ConservativeJustices has posted repeatedly, and again vide supra in this thread, the citations for the fact that the People exist in their States -- not their governments, but the States themselves -- that the People have always existed in and as their States, and that the People have never been amalgamated, nor their ultimate, God-given, fear-no-man Sovereignty given over to any other entity.
The People fear God Himself, and nothing less. Not the federal government which, after all, is just a government, nor the Constitution which is the treaty among the Peoples of the States, nor the Union which is our arrangement among ourselves, nor the Supreme Court, who are our henchmen and paid servants.
Your attempt to wave away the Ninth and Tenth Amendments won't wash. You can't repeal an article of the Constitution by edict, even if you're John Marshall -- and he tried.
Besides, you'd have a hard time selling that argument to Justices Rehnquist, Scalia, and Thomas. They've been very active in rehabilitating the Tenth Amendment, and repairing the damage done by Hamiltonian partisans during the New Deal Era in particular, when the Commerce Clause was used to justify federalizing just about every human activity under the sun.
Try these, there are many more:
Calder v. Bull, 3 U.S. 386 (1798)
Martin v. Hunter's Lessee, 14 U.S. 304 (1816)
Gibbons v. Ogden, 22 U.S. 1 (1824)
Northern Securities Co. v. United States, 193 U.S. 197 (1904)
McCray v. United States, 195 U.S. 27 (1904)
Hammer v. Dagenhart, 247 U.S. 251 (1918)
State of Missouri v. Holland, 252 U.S. 416 (1920)
Bailey v. Drexel Furniture Company, 259 U.S. 20 (1922)
A. L. A. Schechter Poultry Corp. v. United States, 295 U.S. 495 (1935)
United States v. Butler, 297 U.S. 1 (1936)
Ashwander v. Tennessee Valley Authority, 297 U.S. 288 (1936)
Carter v. Carter Coal Co., 298 U.S. 238 (1936) Steward Machine Co. v. Collector of Internal Revenue, 301 U.S. 548 (1937)
Helvering v. Davis, 301 U.S. 619 (1937) United States v. Darby, 312 U.S. 100 (1941)
Morgan v. Virginia, 328 U.S. 373 (1946) Maryland v. Wirtz, 392 U.S. 183 (1968)
United Transportation Union v. Long Island Rail Road Co., 455 U.S. 678 (1982)
Garcia v. San Antonio Metropolitan Transit Authority, 469 U.S. 528 (1982)
Missouri v. Jenkins, 495 U.S. 33 (1990)
Printz v. United States, 521 U.S. 898 (1997)
Reno v. Condon, 528 U.S. 141 (2000)
(my favorite, see Justice Thomas' dissent) US Term Limits, Inc. v. Thornton, 514 US 779 (1995)