The second most important example was the nullification (although they didn’t use that word) after Brown v. Board of Education, which the south basically ignored until Eisenhower sent in the troops (national guard actually) to enforce the SCOTUS decision outlawing school segregation.
Given the current political climate, I’d almost expect the opposite.
Most states get a ton of Federal money for various uses, and I’m sure withholding those funds would be the first step in such a crisis. Often that’s enough. It’s why we have de facto nationwide drinking ages, Interstate highway standards and regulations, BAC limits, ID card standards, etc. The feds just said “we’ll stop giving you all this money if you don’t fall in line”.
That said, there’s a new sheriff in town who seems to actively hate (and actively attempts to obstruct) the very government he runs. That could be a game changer in how the Federal government acts (or fails to act) in these potential Constitutional Crises to keep the States, you know, United. So it seems what the Feds will actually do in such a crisis is definitely open to question nowadays.
As I recall, the North didn’t send any money to the South during the Civil War, except perhaps to purchase George Washington’s property. In fact the South ended up selling bonds and creating its own currency instead. So stopping federal money going to a rebel state probably isn’t going to matter that much. What would matter is embargoing Texas so it can’t sell it goods and products outside of Texas, or may outside of Texas and Mexico. That would certainly strain their financial resources. Of course Texas isn’t a landlocked state so they could sell their stuff internationally until the US put up a blockade in Gulf of America and shut down their commercial airspace.