The united states shall guarantee to every state in this union a republican form of government, and shall protect each of them against invasion."–u. s. constitution according to this quote, the job of protecting the nation from foreign enemies belongs

the local governments
each state government
the national government
international governments

the conditions that made the byzantine empire vulnerable to attacks by the muslin turks were the sack of constantinople by western crusaders, the conquests of the sultanate of rum, presence of rival kingdoms and finally the set up of fiefdoms at the empire which were owned by the ghazis (turkish warriors).

the punishment for breaking the law would depend on the conditions or the seriousness of the law being broken, if he or she breaks the law while doing some great discovery or invention then it would classify as a scientific fraud. there are other words to describe the crime but scientific fraud would be the harshest one.