[SMGFan]

It is unclear exactly how many states the ruling could affect beyond Minnesota. Both Minnesota and the group challenging the state’s law had said there are about 10 states with laws like Minnesota’s, though they disagreed significantly on which ones, agreeing only on Delaware, New Jersey, New York, Texas and Vermont.
https://www.theguardian.com/us-news/2018/jun/14/minnesota-supreme-court-political-clothes-polls-ban

So how and when do we learn if the decision reaches beyond Minnesota?

[jazusamo]

“But when government regulates speech inside a polling place, according to seven of the justices, it must do so reasonably.”

Your guess is as good as mine, maybe when each state decides what is "reasonable" by the seven justices. I don't know.