[billbears]

"The secession of a state from the Union depends on the will of the people of such state....To deny this right would be inconsistent with the principle on which all our political systems are founded, which is, that the people have in all cases, a right to determine how they will be governed."--A View Of The Constitution Of The United States Of America, William Rawle, 1826

The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.--Tenth Amendment

Why, if your premise holds, would the state of Massachusetts, and on a greater scale the New England states during the War of 1812, entertain secession as an option if they knew such an act was illegal?

[The Scourge of Yazid]

I don't think the question is whether they "entertained" secession, but whether they actually seceded. If I were to list every elected official that "entertained" an illegal measure, we'd be here forever. The list would probably start with Gavin Newsome, but I seriously doubt that it would end there.

[Travis McGee]

CW2 (if that national tragedy occurs) will not break out on any kind of neat state lines, permitting a secession option.

It will be more comparable to a free for all melee, with elements of the 1930s Spanish Civil War, the 1970s Argentine "Dirty War," with elements of Bosnia and Kosovo thrown in.