Wasn't this question answered about 150 years ago?
No, the question of whether or not the US would allow
states to exercise their entirely Constitutional right of secession was settled, which is a different thing entirely.
As someone noted above, and declaration of secession would be made by the state
, not by a citizens' petition.
And the SCOUTS ruling is wrong on the facts. If a state wants to leave, under the Constitution as it was plainly understood prior to the 1860s, it was their
decision, and the Federal Congress had no say in it.