It did declare unilateral secession as practiced by the southern states to be illegal. No supposedly to it.
Gee, they're all Yankees, with the exception of Field from California. Kind of makes you wonder, eh?
And that's all the evidence you have? An entirely Yankee court, but a 5 to 3 decision. So what was it? Did Justice Grier, Justice Miller, and Justice Swayne have a rebel in their woodpiles somewhere? And BTW, California remained in the Union, it WAS a Yankee state.
Yeah, the whole spectrum of jurisprudence, from A to E.
And California was a Unionist and freesoiler state; they just didn't participate much in the War because of physical remoteness, though there were one or two deep-raiding incidents mounted by the Confederates (one into Arizona) that might have involved California garrisons.