My brother, the writer told me that that will be an integral part of the whole entire story, as he is deciding whether or not to make you guys go to war with a fictional country or even real (Russia, Germany, China, North Korea). So you will definitely do it a few chapters in. It will be VERY in depth, as in depth as choosing which troops (Army, Navy, Air Force, Navy Seals/Special Forces/Ops) or combat vehicles (bombers, spy aircraft, tanks, submarines, aircraft carriers) to send off and able to specifically choose a city to attack or take over either based on political benefits (like a capitol city) or military or battlefield benefits (like a city close to a seaport, airport, strategic location or allies near a border).
As for your second question, being able to assassinate opponents he said might only make it available against a foreign enemy or roadblock. You could probably spy and bring down domestic rivals/enemies but you can't just assassinate a "problem" without a horrible media firestorm and subsequent arrest and impeachment. Not to mention a huge damage to your reputation. Perhaps if your "Subterfuge" is high enough? (like 100!)