I don't have a source, but upon doing further research the larger problem is the enforcement as countries through various agreements countries only have to give at least as strong protections as they give to their own nationals.
Right, but the treaties set the baseline of enforcement that all countries that sign them need to respect, and Berne convention copyright is already pretty strong. If you make laws stronger than that, they only apply in your own country. That makes a lot of sense.
What makes enforcement difficult then is the cost of legal action… it is already expensive and time consuming in your own country, so it gets really expensive if you want to sue someone abroad, even if, because of copyright treaties, you have standing.
I don't have a source, but upon doing further research the larger problem is the enforcement as countries through various agreements countries only have to give at least as strong protections as they give to their own nationals.