That is from the Articles of Confederation.
The Constitution was to be more more binding, not less.
And Whereas it hath pleased the Great Governor of the World to incline the hearts of the legislatures we respectively represent in Congress, to approve of, and to authorize us to ratify the said articles of confederation and perpetual union. Know Ye that we the undersigned delegates, by virtue of the power and authority to us given for that purpose, do by these presents, in the name and in behalf of our respective constituents, fully and entirely ratify and confirm each and every of the said articles of confederation and perpetual union, and all and singular the matters and things therein contained: And we do further solemnly plight and engage the faith of our respective constituents, that they shall abide by the determinations of the united States in congress assembled, on all questions, which by the said confederation are submitted to them. And that the articles thereof shall be inviolably observed by the States we respectively represent, and that the union shall be perpetual. (emphasis added)
More binding? Earth calling, pick up the phone. They left the perpetual Articles. That wording was left out of the Constitution.
Now.. go ahead and dismiss - St. George Tucker. His work was the cornerstone of the resent second Amendment victories.
....Nor must we forget that solemn declaration to which every one of the confederate states assented . … that whenever any form of government is destructive of the ends of its institution, it is the right of the people to alter or abolish it, and to institute new government. Consequently whenever the people of any state, or number of states, discovered the inadequacy of the first form of federal government to promote or preserve their independence, happiness, and union, they only exerted that natural right in rejecting it, and adopting another, which all had unanimously assented to, and of which no force or compact can deprive the people of any state, whenever they see the necessity, and possess the power to do it.