1. War is only a continuation of state policy by other means (see Carl von Clausewitz, On War).
2. Nations have (at least) four areas of national power they can use to exert their implementation of policy: Diplomatic, Information, Military and Economic. These four "areas of national power" are sometimes referred to as DIME. While we often think of military might as being paramount, successful nations use all four to further their national goals. See the glossary published by the Joint Forces Command.
3. The Rice Doctrine:
The president must remember that the military is a special instrument. It is lethal, and it is meant to be. It is not a civilian police force. It is not a political referee. And it is most certainly not designed to build a civilian society. Military force is best used to support clear political goals, whether limited, such as expelling Saddam from Kuwait, or comprehensive, such as demanding the unconditional surrender of Japan and Germany during World War II. It is one thing to have a limited political goal and to fight decisively for it; it is quite another to apply military force incrementally, hoping to find a political solution somewhere along the way. A president entering these situations must ask whether decisive force is possible and is likely to be effective and must know how and when to get out.Quoted from Dr. Rice's article "Campaign 2000: Promoting the National Interest" published in the January/February 2000 issue of Foreign Affairs.
4. The Powell Doctrine:
When the political objective is important, clearly defined and understood, when the risks are acceptable, and when the use of force can be effectively combined with diplomatic and economic policies, then clear and unambiguous objectives must be given to the armed forces. These objectives must be firmly linked with the political objectives. We must not, for example, send military forces into a crisis with an unclear mission they cannot accomplish....This also from Foreign Affairs and Colin L. Powell's Winter 1992/93 essay "U.S. Forces: Challenges Ahead" and quoted from this City University of New York website.
When force is used deftly--in smooth coordination with diplomatic and economic policy--bullets may never have to fly. Pulling triggers should always be toward the end of the plan, and when those triggers are pulled all of the sound analysis I have just described should back them up....
The reason for our success is that in every instance we have carefully matched the use of military force to our political objectives. We owe it to the men and women who go in harm's way to make sure that this is always the case and that their lives are not squandered for unclear purposes.
Military men and women recognize more than most people that not every situation will be crystal clear. We can and do operate in murky, unpredictable circumstances. But we also recognize that military force is not always the right answer. If force is used imprecisely or out of frustration rather than clear analysis, the situation can be made worse.
Decisive means and results are always to be preferred, even if they are not always possible. We should always be skeptical when so-called experts suggest that all a particular crisis calls for is a little surgical bombing or a limited attack. When the "surgery" is over and the desired result is not obtained, a new set of experts then comes forward with talk of just a little escalation--more bombs, more men and women, more force. History has not been kind to this approach to war-making. In fact this approach has been tragic -- both for the men and women who are called upon to implement it and for the nation. This is not to argue that the use of force is restricted to only those occasions where the victory of American arms will be resounding, swift and overwhelming. It is simply to argue that the use of force should be restricted to occasions where it can do some good and where the good will outweigh the loss of lives and other costs that will surely ensue. Wars kill people. That is what makes them different from all other forms of human enterprise.