Well then they made a mistake. If they wanted to assure it was "perpetual" they should have included a prohibition of secession in the document.
And they DID discuss it.
I am not taking a side in this one, just want to get some info. Do you have a link showing the framers of the constitution discussed the issues of seccesion? I know certains states had a provision concerning secession in thier acceptance of the constitution, but when did the framers discuss it and what was said?
The Union was declared "perpetual" under the Articles.
The Constitution was created to STRENGTHEN that Union.
Allowing secession would WEAKEN that Union.
Therefore, secession is contrary to the spirit of the Constitution and would be completely inconsistent with the intent to make "more perfect" that Union. Makes no sense that the Founders would have worked against their goal.
Since secession was unthinkable to them there was no reason they would have put such a thing into the Constitution. Insurrection covered it sufficiently.