[rustbucket]

If the founders wanted to give the southern states the right to unilaterally secede then they would have done so clearly, given how much it differs from the other articles of the Constitution. Now wouldn't they?

Connecticut Republican Congressman Ferry apparently didn't read the memo. He introduced or tried to introduce the following resolution in the House on February 9, 1861:

Resolved, that the Committee on the Judiciary be instructed to inquire into the expediency of so amending the Constitution of the United States as expressly to forbid the withdrawal of any State from the Union without the consent of two thirds of both Houses of Congress, the approval of the President, and the consent of all the States, to report by joint resolution proposing such an amendment, or otherwise.

[Non-Sequitur]

He introduced or tried to introduce the following resolution in the House on February 9, 1861...

It didn't get very far, did it? Probably because it wasn't necessary.