How we change what others think, feel, believe and do
'Force multiplication' is a simple principle in warfare that dramatically increases the power of the forces that you have at your disposal.
A problem in warfare is in how to use the limited resources at you disposal. Forces are almost always short as demand exceeds supply, for example where regiments are spread across multiple fronts or where you just have a small military force in comparison with your enemy.
The problem is then how to maximize the force that you have.
The basic principle of force multiplication is to find and use factors that increase the effective power that you have (or reduce that of your opponents). Using multiple multipliers has an even greater effect, such that a well-multiplied small force can successfully take on a much larger force.
Whilst you have limited people, you can make them more effective in many ways, such as ensuring they are well trained and optimally equipped.
A particularly powerful people-based multiplier is morale. A charged-up group of people will fight far more fiercely, increasing the chance both of success and also of demoralizing the opponents.
Technology can provide many advantages, from satellite pictures of enemy deployment to advanced weaponry.
A well-equipped soldier alone is far more powerful than one with just a basic weapon, especially when trained and deployed effectively. Add to this the backup of motorized equipment, computers, range-finders and so on, and a small group can have a huge effect.
There are always natural resources around, and even at the immediate tactical level, soldiers will use the shape of the ground for cover and may at worst use sticks and stones for makeshift weapons.
More strategically, mountains, lakes, rivers and other geographic features should always be included in battle planning. The weather can also be used, for example attacking when the cold and wet has driven the other side indoors.
Psychological methods can always increase your power. First, as above, motivating your own force can make them more effective. People who think they will lose are more likely to lose. And if they believe they can win, then this will give them confidence (of course the danger of gung-ho over-confidence should be managed carefully).
It can be very powerful also to find ways to demoralize the other side, from the surprise and ferocity of your attacks that builds a fearsome reputation to the subtle use of propaganda and other forms of deception that sap confidence and make them think you are more powerful than perhaps you are.
Techniques for changing minds can be powerful force multipliers, whether they are for boosting morale of troops, creating support in local populations or demoralizing the enemy. Propaganda is a classic wartime persuasive force multiplier.
Strategies and tactics
There are many other strategies and tactics that can be used to increase your ability, such as the use of guerilla methods in asymmetrical warfare. In fact the main purpose of most strategies and many tactics is to make the most of what you have, whilst decreasing the ability of your enemy.
A classic historical approach was taken by Leonides who held back the vastly more powerful Persian army of Xerxes at Thermopylae in 480BC by holding a 'pinch-point' where the mountains came very close to the sea.