Professor Williams may be a fine economist, but he is not a very good historian. His article has been thoroughly debunked here at FR, and continues to be each time it rears its ugly head. Unilateral secession is not lawful.
On the other hand, if the people want to invoke their revolutionary rights to throw off an "oppressive" and "tyrannical" government, then they had better be prepared to fight for those rights, because those who support republican democracy and the rule of law are not going to be any more understanding than they were 143 years ago.
Garbage. Texas v. White was ruled against secession, but beyond that point it has precious little going for it. The case's internal logic is a nightmare of inconsistency and contradiction placing it in that category of truly bad and poorly written cases where you will find such names as Plessy and Roe.
Besides, given the timing of that case do you honestly think that the supreme court could have ruled any other way? Had they done so they would have completely undermined everything the yankees spent the last four years fighting for and potentially even risked reigniting the war. So instead they draft up a weak and self-referentially inconsistent damnatio memoriae on the confederacy to push the issue under the carpet. As to Williams being "debunked" here at FR, I certainly haven't seen it and if that is to be taken as a claim that you or any other member of the Wlat brigade has done the "debunking" it may be dismissed as a matter of absurdity...unless by "debunking" you mean making up court cases, amending existing rulings, trumping up false charges against harassed judges, making up non-existant battles, and changing the name of units in the federal army into "militias" on a whim as it suits the convenience of your desired position.