One of its -stated- purposes is to make the Union more perfect.
"As he hears his own lips parroting the sad cliches of 1850 does the Southerner sometimes wonder if the words are his own? Does he ever, for a moment, feel the desperation of being caught in some great time machine, like a tread mill, and doomed to eternal effort without progress? Or feel, like Sisyphus, the doom of pushing a great stone up a hill only to have the weight, like guilt, roll back over him, over and over again? When he lifts his arms to silence protest, does he ever feel, even fleetingly, that he is lifting it against some voice deep in himself?"
-- Robert Penn Warren, The legacy of the Civil War", p.56-57
Walt
It would be a strange concept of perfection according to which member states remaining in the union only under coercion would make it more perfect than would their withdrawal. Or, in other words, a perfect union would be made up of members that belonged to the union voluntarily.