Attack to enemy soldier

Hi. I have very hard problem(for me). I making a strategy game like Europa Universalis. I have selected a nation (example Britons). When game start, Britons at war with France. Now my war system is:

//its English Gameobject

public GameObject AtWar[];

I attach France Gameobject to English gameobject's AtWar var.

Now Its My Problem: soldier AI:

 public float distance;
 GameObject nearest;
 
 GameObject FindClosestEnemy() {
         GameObject[] gos;
         gos = GameObject.FindGameObjectsWithTag("AtWarEmpire");
         GameObject closest=null;
         float distance = Mathf.Infinity;
         Vector3 position = transform.position;
         foreach (GameObject go in gos) {
             Vector3 diff = go.transform.position - position;
             float curDistance = diff.sqrMagnitude;
             if (curDistance < distance) {
                 closest = go;
                 distance = curDistance;
             }
         }
         nearest=closest;
         return closest;
     }
 void Update(){
 distance=Vector3.Distance(gameObject.transform.position,nearest.transform.position);
 if (distance<10){
 transform.position = Vector3.MoveTowards(transform.position, yakin2.position, 3*Time.deltaTime);
 }
 }

I wanna make this:

Soldier find nearest AT WAR empire's soldier.

how to i can make this?

Sorry for bad English