If the US would take down .se as a whole, big diplomatic issues would arise immediately, with the end result of either removing root server control from the US or a split of the domain system (between the US and an opposing global entity). But even then, as long as people inside Sweden have their computer pointed up to their ISP dns server which in turn has it pointed to the .se dns server, turning off .se in the root server would not stop swedish people from using swedish sites without any interruption.
They risk sparking a diplomatic incident if they were to try to take down a .ccTLD domain. Non-USA based root servers would not have to abide by USA rules, and in fact, local websites might get court injunctions to force ISPs to continue to resolve example.xx into what ever was there before. This means whether a domain resolves depends on what DNS servers you talk to.
What your describing might fragment the DNS system into multiple different ones.