Lincoln did articulate a view of secession that would have been heartily endorsed by the Confederacy: "Any people anywhere, being inclined and having the power, have the right to rise up and shake off the existing government and form a new one that suits them better. ... Nor is this right confined to cases in which the whole people of an existing government may choose to exercise it. Any portion of such people that can may revolutionize and make their own of so much of the territory as they inhabit." Lincoln expressed that view in an 1848 speech in the U.S. House of Representatives, supporting the war with Mexico and the secession of Texas.
Thus, according to Lincoln and Williams, the right to secession or independence is dependent upon the power to successfully effectuate the change. Neither Lincoln nor Williams suggests that an existing government cannot or should not resist an attempt to secede or an attempt to declare independence.
And, that's what happened. Some Southerners attempted to secede, the existing government resisted and the existing government prevailed.
Anyone has the ability to attempt to resist or to overthrow the existing government in a geographical area. As long as you acknowledge that the existing government has a right to defend itself, there is nothing particularly controversial about any of this. I think the controversy surrounds the suggestion by some that the existing government cannot properly contest an attempted secession or declaration of independence.
If that is your argument, then you need to shut up about any other rational.
If you truly believe that power is the only deciding factor, you have no business debating the topic. Why don't you save both you and us a lot of time and come down on one side or the other.
If in your opinion, *POWER* is not the deciding factor, then shut up about it. Stop putting it forward as your argument.