Invasion

In antiquity, before radio communications and fast transportation, the only way for a military to ensure adequate reinforcements was to move armies as one massive force.

[2] Before the days of package tours and cut-price airlines, military invasions functioned as a standard major form of proto-tourism[3] – bringing large numbers of foreign visitors into new environments, with the consequential social, cultural and economic impacts on indigenous populations and on the invaders.

[4] However, these barriers can require a large military force to provide the defense, as well as maintain the equipment and positions, which can impose a great economic burden on the country.

These structures are designed to delay an invasion long enough for the defending nation to mobilize an army of a size sufficient for defense or, in some cases, counter-invasion—such as, for example, the Maginot Line.

[citation needed] In particularly large nations, the defending force may also retreat to facilitate a counterattack by drawing the invaders deeper into hostile territory.

Other, more subtle, preparations may involve secretly garnering popular support, assassinating potentially threatening political or military figures, and closing off supply lines where they cross into neighboring countries.

In some cases, those other means of attack eliminate the need for ground assault; the 1945 atomic-bombing of Hiroshima and Nagasaki ultimately made it unnecessary for the Allies to invade the Japanese home islands with infantry troops.

In cases such as this, while some ground troops are still needed to occupy the conquered territory, they are allowed to enter under the terms of a treaty and as such are no longer invaders.

However, the large amount of specialized equipment, such as amphibious vehicles and the difficulty of establishing defenses—usually with a resulting high casualty count—in exchange for a relatively small gain, are often used as arguments against such an invasion method.

However, even with such a massive force taking the Germans completely by surprise, the assault was a tactical failure and after 9 days of fighting the Allies managed only to escape back to their own lines, having sustained over 18,000 casualties.

Once political boundaries and military lines have been breached, pacification of the region is the final, and arguably the most important, goal of the invading force.

[citation needed] Media propaganda such as leaflets, books, and radio broadcasts can be used to encourage resistance fighters to surrender and to dissuade others from joining their cause.

This may be accomplished through reeducation, allowing conquered citizens to participate in their government, or, especially in impoverished or besieged areas, simply by providing food, water, and shelter.

Sometimes displays of military might are used; invading forces may assemble and parade through the streets of conquered towns, attempting to demonstrate the futility of any further fighting.

For example, Bobby Sands, who died during a hunger strike in Long Kesh prison, became a symbol of the Provisional Irish Republican Army.

Before his invasion of Greece, Xerxes I spent three years amassing supplies from all over Asia; Herodotus wrote that the Persian army was so large it "drank the rivers dry".

During the Second Punic War, for example, Hannibal diverted his army to conquer cities simply to gather supplies; his strategy in crossing the Alps necessitated traveling with as few provisions as possible, expecting the Roman stores to sustain them when they had breached the border.

Even as rules become stricter, the necessities of war become more numerous; in addition to food, shelter, and ammunition, today's militaries require fuel, batteries, spare mechanical parts, electronic equipment, and many other things.

[citation needed] The development of Morse Code, and later of voice communications by radio and satellite, have allowed even small units of skirmishers to remain in contact with a larger invasion force, to verify orders or to call for artillery support and air strikes.

In contrast, in modern times, a defender can improve public relations with a right message: Ukrainanian President Volodymyr Zelenskyy's popularity was suffering after years of his presidency, but during the Russian invasion of Ukraine in 2022 his popularity improved dramatically, while Putin's image of a calculating strategist was damaged and Russia was growingly being seen as a pariah in the international stage.

This theory acknowledges that these changes may take time—generations, in some cases—but holds that immediate benefits may still be won by reducing membership in, and choking the supply lines of, these covert cells.

Proponents of the invasion strategy in such conflicts maintain the belief that a strong occupying force can still succeed in its goals on a tactical level, building upon numerous small victories, similar to a war of attrition.

[19] They also cite continuing conflicts such as Northern Ireland, Israel, Chechnya, and Iraq, as well as examples which they claim ultimately proved to be failures, such as Lebanon, and Afghanistan.

In other cases the results of a successful invasion may simply be a return to the status quo; this can be seen in wars of attrition, when the destruction of personnel and supplies is the main strategic objective,[22] or where a nation previously subdued and currently occupied by an aggressive third party is restored to control of its own affairs (i.e. Western Europe following the Normandy landings in 1944, or Kuwait following the defeat of Iraq in 1991).