### Clue: Recently created nation in trouble using non-relativistic laws (9)
### Answer: NEWTONIAN 
 ### Explanation: Definition: using non-relativistic laws
  NEW(recently created) + **anagram of**(in trouble) NATION. 
Answer: Descriptive of the laws of physics discovered by Isaac Newton, later shown by Einstein, to be applicable only if relativity may be ignored, ie. in non-relative circumstances, which includes almost all of what we experience.