Light infantry

Traditionally light infantry (or skirmishers) were soldiers whose job was to provide a skirmishing screen ahead of the main body of infantry, harassing and delaying the enemy advance. Light infantry was distinct from medium, heavy or line infantry. Heavy infantry were dedicated primarily to fighting in tight formations that were the core of large battles. Light infantry often fought in close co-ordination with heavy infantry, where they could screen the heavy infantry from harassing fire, and the heavy infantry could intervene to protect the light infantry from attacks of enemy heavy infantry or cavalry. Heavy infantry originally had heavier arms and more armour than light infantry, but this distinction was lost as the use of armour declined and gunpowder weapons became standardized.&lt;ref&gt;&lt;/ref&gt;

Antiquity
The concept of a skirmishing screen is a very old one and was already well-established by Greek and Roman times in the form, for example, of the Greek peltast and the Roman velites. As with so called 'light infantry' of later periods, the term more adequately describes the role of such infantry rather than the actual weight of their equipment. Peltast equipment for example grew steadily heavier at the same time as hoplite equipment grew lighter. It was the fact that peltasts fought in open order as skirmishers that made them light infantry, and that hoplites fought in the battle line as a phalanx that made them heavy infantry.

Modern age
Regular armies usually relied on irregulars to perform the duties of light infantry skirmishers. Later, the dragoons of the 17th century were the light infantry skirmishers of their day – lightly-armed and armoured infantrymen who rode into battle but dismounted to fight.

In the 18th and 19th centuries most infantry regiments or battalions had a light company. Its members were often smaller, agile men, or soldiers with extensive combat experience, capable of using initiative, since they did not always fight in disciplined ranks as did the ordinary infantry but often in widely dispersed groups. They were also often chosen for their shooting ability and sometimes carried lighter muskets than ordinary infantrymen. Some light infantry units carried rifles instead of muskets, and wore rifle green uniforms; they became designated as rifle regiments in Britain and Jäger (hunter) regiments in German speaking Europe. In France, during the Napoleonic Wars, light infantry were called voltigeurs and the sharpshooters tirailleurs.

Unusually, light infantry officers sometimes carried muskets as well and their swords were lighter and curved sabres; as opposed to the heavy, straighter swords of other infantry officers. Orders were sent by bugle or whistle instead of drum (since the sound of a bugle carries further and it is difficult to move fast when carrying a drum). Some armies, including the British and French, converted whole regiments into light infantry. These were sometimes considered elite units, since they required more training and self-discipline to carry out the roles of light infantry as well as those of ordinary infantry. During the period 1777-1781, the Continental Army of the United States adopted the British Army practice of seasonally drafting light infantry regiments as temporary units during active field operations, by combining existing light infantry companies detached from their parent regiments.

By the late 19th century the concept of fighting in formation was on the wane and the distinctions between light and heavy infantry began to disappear. Essentially, all infantry became light infantry in practice. Some regiments retained the name and customs, but there was in effect no difference between them and other infantry regiments.

Light infantry today
Today the term "light" denotes the table of organization and equipment defining units lacking heavy weapons, armor and/or a reduced vehicle footprint. Light infantry units lack the lethality, tactical mobility and survivability of heavy units, but possess greater strategic mobility and the ability to execute missions under restrictive terrain and weather that may otherwise impair a heavy unit's mobility. Light infantry forces typically rely on their ability to operate under restrictive conditions, surprise, violence of action, training, stealth, field craft, and fitness level of the individual soldier to address their reduced lethality. Ironically, forces in a light unit will normally carry heavier individual loads versus other forces; literally they must carry everything they require to fight, survive and win due to lack of vehicles.

In the 1980s, the United States Army increased light forces to address contingencies and increased threats requiring a more deployable force able to operate in restrictive environments for limited periods. At its height, this included the 10th Mountain Division (Light Infantry), 7th Infantry Division (Light), 25th Infantry Division, 6th Infantry Division (Light), and other battalion and brigade combat teams in mixed heavy/light units. Operation Just Cause is often cited as proof of concept. Almost 30,000 U.S. Forces, mostly light, deployed to Panama within a 48 hour period to execute combat operations.

During the 1990s the concept of purely light forces came under scrutiny due to their decreased lethality and survivability. This scrutiny has resulted in the Stryker Brigade Combat Team, a greater focus on task organized units (such as Marine Expeditionary Units) and a reduction of purely light forces.

Despite their reduction, light forces have proven successful in Afghanistan (Operation Enduring Freedom), underlining the continued need for light infantry.

Examples of current light units:


 * seaborne or ship-based units, such as the United States Marine Corps' MEU (SOC) or the Royal Marines Commandos, and Britain's Special Forces Support Group or 3 Commando Brigade.
 * infantry intended for difficult terrain such as mountains (see 10th Mountain Division, 86th Infantry Brigade Combat Team (Mountain), 1st Marines) or jungle.
 * internal security or paramilitary troops and police field forces.
 * troops involved in guerrilla or counter-guerrilla warfare.
 * home defense or militia.

Note that in some armies Light Infantry are usually considered as an elite, but in other countries they may be considered inferior due to their lack of equipment.