A lot of interesting falsehoods scattered among the historical facts in that link.
Assertion: Secession was Lincoln’s fault for being elected.
Fact: Pretended secession of several states took place before Lincoln took office. Lincoln can hardly be blamed for the Democratic Party’s breakup on the issue of slavery. Of course the southern partisan’s devotion to slavery can be blamed for the Democratic Party’s breakup.
Assertion: Ft Sumter was built on foreign soil.
Fact: Ft. Sumter was built on a shoal, built up with stone from NY and MA, with the cost borne by the Union, with most taxes collected in northern ports.
Assertion: US Constitution ended the Perpetual Union of the Articles of Confederation.
Fact: US Constitution itself states that it makes the Union “more perfect”. What union would that be? The existing perpetual union is the only one to hand.
Secession could be legally accomplished under the Constitution, but only certainly by amendment approved by 3/4s of the states, or by treaty or possibly by federal, or possibly by federal court case. Legal secession by federal action was thought to be so unlikely that illegal acts of secession were adopted, and armies raised by the south to support rebellion. Rebellion could have, if successful, led to a treaty with the US, giving legal status to the pretended Confederacy. Since they didn’t win their rebellion, they didn’t get that treaty, and thus remain an illegal nullity.
No contract can be abrogated at will by a single party to it. If it was so, then there would be no reason to have a contract. The US constitution has within it, means to resolve issues between the states, or between the states and the federal Constitution. Issues involving states are resolved with the Supreme Court as original jurisdiction.
That is why one of the legal means to secession is by court case.
Pro-Confederate Propaganda Central