[Dr. Franklin]

The defendants had argued that the Supreme Court did not have original jurisdiction in the case because Texas' current situation was not that of a state as contemplated by the Founders, but was that of a territory secured by military conquest. So the question on whether Texas was a state was certainly a matter before the court and central to the ultimate decision.

But it was sufficient that Texas had again been considered a state, in some form, after Lee's surrender and Union military occupation. The issue of secession was not necessarily for SCOTUS to claim original jurisdiction, and thus it was so much dicta. Since Texas had been required to apply for readmission to the Union in order for its representatives to take office in Congress, Chase's argument is counterfactual. Only an idiot would argue to the contrary:
An Act to admit the State of Texas to Representation in the Congress of the United States. March 30, 1870

[Dr. Franklin]

The issue of secession was not necessarily for SCOTUS to claim original jurisdiction, and thus it was so much dicta.

The issue of secession was not necessary to decide for SCOTUS to claim original jurisdiction, and thus it was so much dicta.

[DoodleDawg]

The issue of secession was not necessarily for SCOTUS to claim original jurisdiction, and thus it was so much dicta.

The claim was that Texas was not a state under the Constitution but was an occupied territory. And as such the Supreme Court did not have original jurisdiction. So the question of whether Texas was a state was a matter before the court, and the legality of the Texas secession was central to answering that question. So ruling on secession was also a matter for the court to decide. If the manner in which Texas seceded was illegal then Texas never left the Union. If it never left the Union then it remained a state even while engaged in rebellion. If it was always a state then the Supreme Court had original jurisdiction in this case. All is central to the matter before the court so none of the Chief Justice's comments were made in dicta.

Since Texas had been required to apply for readmission to the Union in order for its representatives to take office in Congress, Chase's argument is counterfactual. Only an idiot would argue to the contrary:

An Act to admit the State of Texas to Representation in the Congress of the United States. March 30, 1870

Since you have decided to resort to insults then I'll merely point out than only an idiot would confuse an enabling act that admits a state to the union with legislation restoring the rebellious state's Congressional delegation to Congress which was required by the Reconstruction Acts.