Nothing has to push them. These countries want to go nuclear. The only thing preventing them is the threat of american intervention. Japan and South Korea had secret nuclear programs that we put a stop to. Canada, Brazil and Mexico will never be allowed to own nukes. No nation in the western hemisphere will allowed to own nukes outside the US. As for germany and the netherlands, we'd sanction and isolate them if they ever developed nukes. They could have nukes, but their economy would be in shambles like north korea. If taiwan went nuclear then it would be the end of taiwan and both the US and china would take them out.