AP--

As you know, Realism assumes that the state can/must be treated as if it were a single, individual actor who is rationally pursuing his interests. Granted, there are many flaws in that assumption as Entropy and Selil have pointed out, but it works well most of the time. (I use 80% as my ballpark estimate.) So, as long as you demonstrate that you are aware of the possible pitfalls with an explantory note or in the text itself, you should be fine. As a professor of political science at U of MD told my wife when she was a PhD candidate, "Done is better than perfect."

Drive on!

Cheers

JohnT