From context, I assume an incident involving someone crossing state lines or not to recruit Union members, which has relevant implications for which laws and legal jurisdictions are applicable.
No, it’s about a recent, popular self-defense case in which many people wanted the victim to be found guilty, and they would talk about how he “crossed state lines” as though crossing state lines was some ominous, evil thing. This “crossed state lines” rhetoric was even parroted by the media, and eventually it became a meme as people used it sarcastically.
Crossing state lines really does have certain jurisdiction / formal legal implications. In particular it upgrades the matter from state to the federal judicial system, which usually entails higher stakes for the defendant. If some group wants to see a particular individual punished for whatever reason, then naturally they would want him to have tripped over the technicality that would make his situation far worse. It has nothing to do with crossing the state line being a heinous act in itself.
I nailed everything from context except the particular crime being alluded to.
Transporting weapons or controlled substances over state lines has legal implications, but not in a murder/self-defense trial. The “crossed state lines” was just a fall-back to make it sound like the victim did something abhorrent or went well out of his way to get into trouble.
