Editing Invasion (section)

==Support==

===Logistics===
[[File:Выдвижение танкового подразделения в Киевской области в ходе вторжения на Украину 006.png|thumb|Russian convoy in Kyiv region, during 2022 invasion.]]
Without a steady flow of supplies, an invading force will soon find itself retreating. Before his invasion of [[Ancient Greece|Greece]], [[Xerxes I of Persia|Xerxes I]] spent three years amassing supplies from all over Asia; [[Herodotus]] wrote that the [[Persian Empire|Persian]] army was so large it "drank the rivers dry".<ref>{{cite web| author=Rowland, Stephen| title=Persian society in the time of Darius and Xerxes| year=2005| url=http://hsc.csu.edu.au/ancient_history/societies/near_east/2498/persian_army.html| access-date=February 24, 2006| archive-url=https://web.archive.org/web/20060224010215/http://hsc.csu.edu.au/ancient_history/societies/near_east/2498/persian_army.html| archive-date=February 24, 2006| url-status=dead| df=mdy-all}}</ref>

In most invasions, even in modern times, many fresh supplies are gathered from the invaded territories themselves. Before the [[laws of war]], invaders often relied heavily on the supplies they would win by conquering towns along the way. 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 Republic|Roman]] stores to sustain them when they had breached the border.<ref>{{cite web | author=Polybius| title=The Histories, Book III| year=1922 | url = https://penelope.uchicago.edu/Thayer/E/Roman/Texts/Polybius/3*.html#100|access-date=February 24, 2006}}</ref> The [[scorched earth]] tactics used in Russia forced [[Napoleon I of France|Napoleon]] to withdraw his forces due to lack of food and shelter. Today, the [[Law of land warfare]] forbids [[looting]] and the confiscation of private property, but local supplies, particularly perishables, are still purchased when possible for use by occupying forces, and airplanes often use parachutes to drop supplies to besieged forces. 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. In the United States, the [[Defense Logistics Agency]] employs over 22,000 civilians with the sole task of logistics support, and 30,000 soldiers graduate from the [[U.S. Army Logistics Management College]] each year.<ref>{{cite web| author=U.S. Army| title=Background of ALMC| year=2005| url=http://www.almc.army.mil/| access-date=February 24, 2006| archive-date=February 23, 2006| archive-url=https://web.archive.org/web/20060223002905/http://www.almc.army.mil/| url-status=dead}}</ref>

===Communication===
[[File:SOTM.jpg|thumb|right|A mobile satellite communications center]]
Another consideration is the importance of leadership being able to communicate with the invasion force. In ancient times, this often meant that a king needed to lead his armies in person to be certain his commands were timely and followed, as in the case of [[Alexander the Great]] (356–323 BCE). At that time, the skills needed to lead troops in battle were as important as the skills needed to run a country during peacetime. When it was necessary for the king to be elsewhere, messengers would relay updates back to the rear, often on horseback or, in cases such as the [[Battle of Marathon]] (490 BCE), with swift runners.{{citation needed|date=April 2014}}

When possible, [[sloop]]s and [[Cutter (ship)|cutters]] were used to relay information by sea. {{HMS|Pickle}} brought Britain the first news that [[Horatio Nelson, 1st Viscount Nelson|Nelson]] had defeated the French forces at the [[Battle of Trafalgar]] in 1805.{{citation needed|date=April 2014}}

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. These communications were critical to the German [[blitzkrieg]] strategy, as infantry commanders relayed defensive positions to tanks and bombers.{{citation needed|date=April 2014}}

=== Public relations ===
[[File:President Zelenskyy says Russia is a grave threat to the European way of life (52678467391).jpg|thumb|President of Ukraine [[Volodymyr Zelenskyy]] addressing the European Parliament during an extraordinary plenary session in Brussels.]]
In diplomatic, public relations and propaganda terms, it may help an invader (or a potential invader) to have an invitation as an excuse to intervene with a view to "restoring order" or "righting wrongs". Dissident groups, [[fifth column]]s or official circles may conspire to "call in" foreign assistance. Cases include:
* From the point of view of the [[Byzantine Empire]], the [[First Crusade]]'s invasion and conquest of the Levant (1096–1099) resulted from an invitation issued by Emperor [[Alexios I Komnenos]] in 1095, seeking assistance against the Turks in Anatolia.
* English barons opposed to King [[John of England|John]] invited the French Prince [[Louis VIII of France|Louis]] to undertake a French invasion of England in the [[First Barons' War]] of 1215–1217.
* In 1688 an [[invitation to William]] of Orange to invade Britain helped the [[Glorious Revolution]].
* [[Wolfe Tone]] asked for French intervention (the unsuccessful [[Expédition d'Irlande]], 1796) in the lead-up to the [[Irish Rebellion of 1798]].
* Some members of the [[Communist Party of Czechoslovakia]] allegedly called for Soviet intervention during the [[Prague Spring]] of 1968, which ended with the [[Warsaw Pact invasion of Czechoslovakia]] in August 1968.

National foundation-legends can echo the theme of inviting foreign warriors to come and rule a people: note the traditional account in the ''[[Tale of Bygone Years]]'' of how [[Varangian]] invaders came establish long-term rule in [[Veliky Novgorod|Novgorod]] (and subsequently throughout [[Russia]]).

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 state|pariah in the international stage]].<ref>{{Cite web |last=LINTHICUM |first=KATE |last2=BULOS |first2=NABIH |date=2022-02-28 |title=Ukraine is winning — at least in the public relations battle |url=https://www.latimes.com/world-nation/story/2022-02-27/zelensky-is-beating-putin-at-least-in-the-public-relations-battle |access-date=2023-07-21 |website=[[Los Angeles Times]] |quote=The war for Ukraine may be far from decided, but in the public relations battle, Zelensky is clearly winning. [...] As a possible conflict with Moscow loomed in recent months, many Ukrainians wondered whether Zelensky had the steel nerves a wartime president needed to keep the country together against the formidable Russian force [...] But in the four days since Russia invaded, Zelensky has shone}}</ref>