and under these limitations, have the people of each state in the Union a right to secede from the confederated Union itself."
What limitations and qualifications? Perhaps it is as the Declaration of Independence argues:
The right to dissolve the Political Bands which have connected them with another depends on three conditions:
a. Whenever any Form of Government becomes destructive of these Ends (securing unalienable rights). But not to be changed for light and transient Causes.
b. They can right themselves by abolishing the Forms to which they are accustomed.
c. They declare the causes which impel them to the Separation.
Neither Adams nor Jefferson would have argue that there is a right to separation the chief purpose of which was to perpetuate and expand chattel slavery.
To quote Lysander Spooner:
“If it really be established, the number of slaves, instead of having been diminished by the war, has been greatly increased; for a man, thus subjected to a government that he does not want, is a slave. And there is no difference, in principle—but only in degree—between political and chattel slavery.”
Every natural right not expressly given up, or, from the nature of a social compact, necessarily ceded, remains.” Samuel Adams
On that note: The power to prevent secession was voted down. During the Federal Convention and 1861 (see below ).
28 nays to 18 yeas
"Under this Constitution, as originally adopted and as it now exists, no State has power to withdraw from the jurisdiction of the United States; and this Constitution, and all laws passed in pursuance of its delegated powers, are the supreme late of the land, anything contained in any constitution, ordinance, or act of any State to the contrary notwithstanding."
http://memory.loc.gov/cgi-bin/ampage?collId=llsj&fileName=052/llsj052.db&recNum=378&itemLink=D?hlaw:3:./temp/~ammem_iHF8::%230520379&linkText=1