When the Constitution was penned, the founders failed to address the contentious issues of slavery and secession. Arguments pro and con for both slavery and secession continued until they were de facto made illegal with the end of the Civil War.
Slavery was officially abolished Dec. 6, 1865, with the ratification of the 13th Amendment, but it wasn’t until 1869 unilateral secession became illegal when the Supreme Court ruled on the case Texas v. White. (Texas v. White was a case regarding the legality of U.S. government bonds sold to Texas in 1850 but later sold to supplement the Confederacy after having seceded from the Union.)
In lieu of the many deaths, destruction and misguided causes, the Civil War fortunately resulted in the abolition of slavery and the preservation of the Union. However, because unilateral secession had not been addressed by the Constitution nor codified by the Supreme Court prior to the secessions of 1860, it is inaccurate to use terms like traitor and treason when discussing secession by the South.
Malcolm Johnston, Lakeland