Subsidiarity

1. (in the Roman Catholic Church) a principle of social doctrine that all social bodies exist for the sake of the individual so that what individuals are able to do, society should not take over, and what small societies can do, larger societies should not take over

2. (in political systems) the principle of devolving decisions to the lowest practical level

3. The principle that a central authority should have a subsidiary function, performing only those tasks which cannot be performed at a more local level

4. The situation where decisions are made by the people closest to the people affected by these decisions. Ideally, the people that make the decisions (as a group) are the people that are affected by these decisions. Switzerland is the only country where this happens in practice.

Source [3] - The Language of Liberty Institute

Word etymology
subsidiary (adj.) Look up subsidiary at Dictionary.com
1540s, from Latin subsidiarius "belonging to a reserve, of a reserve, reserved; serving to assist or supplement", from subsidium "a help, aid, relief, troops in reserve" (see subsidy). In Latin the word was used as a noun meaning "the reserve".
[Source Online Etymology Dictionary Retrieved June 24, 2017 from etymonline.com website http://www.etymonline.com/index.php?term=subsidiary&allowed_in_frame=0]

Word Origin and History for subsidiarity
n. 1936, from German Subsidiarität, paraphrasing the Latin of Pius XI in his Quadragesimo Anno of 1931; see subsidiary + -ity.
Just as it is gravely wrong to take from individuals what they can accomplish by their own initiative and industry and give it to the community, so also it is an injustice and at the same time a grave evil and disturbance of right order to assign to a greater and higher association what lesser and subordinate organizations can do. For every social activity ought of its very nature to furnish help (Subsidiarität) to the members of the body social, and never destroy and absorb them.
[Pius XI, Quadragesimo Anno, 1931]
[Source Collins English Dictionary - Complete & Unabridged 10th Edition. Retrieved June 24, 2017 from Dictionary.com website http://www.dictionary.com/browse/subsidiarity]

Ambiguity

This principle is often misunderstood to refer simply to the furnishing of aid (or “subsidies”) to those in need. In fact, its main intent is very different. Subsidiarity is a principle that limits government activity to what is strictly necessary, favoring the lower levels of society to take responsibility for everything that they can.

Even though the word “subsidiarity” entered our political vocabulary only in the last century, the idea has an intellectual history as old as European political thought. Its origins can be traced as far back as classical Greece, and is later taken up by Aquinas and medieval scholasticism. Johannes Althusius developed the principle in connection with his theories of the secular federal state in the seventeenth century, and one can find subsequent echoes of it in the thought of political actors and theorists as varied as Montesquieu, Locke, Tocqueville, Lincoln, and Proudhon.

The Latin term originated in the military system of the legions of the Roman Empire — the subsidium was that portion of the troops held in reserve, to be able to assist the front lines when in need — but came also to mean more generally “support,” “help,” “assistance,” or “protection.”

The Roman Catholic Church, which is now more often associated with globalism, has been the major proponent of this core principle.

[Teodor Malloch, quotation from the speech delivered in the building of the Senate of the Republic of Poland, on 2017.05.12]

A military reserve, reserve formation, or simply reserve, is a group of military personnel or units which are initially not committed to a battle by their commander so that they are available to address unforeseen situations or exploit sudden opportunities. Such forces may be held back to defend against attack from other enemy forces, to be committed to the existing battle if the enemy exposes a vulnerability, or to serve as relief for troops already fighting. Some of the different categories of military reserves are: tactical reserve, operational reserve, strategic reserve.

Not to be confused with military reserve force.

[Wikipedia 2017.06.29]

• Benign neglect

By intervening directly and depriving society of its responsibility, the Social Assistance State leads to a loss of human energies and an inordinate increase of public agencies, which are dominated more by bureaucratic ways of thinking than by concern for serving their clients, and which are accompanied by an enormous increase in spending. In fact, it would appear that needs are best understood and satisfied by people who are closest to them and who act as neighbours to those in need.

From Centesimus annus

Centesimus annus (Latin for "hundredth year") is an encyclical which was written by Pope John Paul II in 1991 on the hundredth anniversary of Rerum novarum, an encyclical issued by Pope Leo XIII in 1891. It is part of a larger body of writings, known as Catholic social teaching, that trace their origin to Rerum novarum and ultimately the New Testament.

A film analysing combat properties of Roman Legion and Macedonian Phalanx

Philip V of Macedon was personally leading his phalanx on the ridge at Cynoscephalae and Seleucid Emperor Antiochus III charged at the head of his cataphractii (heavy) cavalry at Magnesia, essentially copying their famous progenitor Alexander himself. This focus on the personal heroism of a Hellenistic monarch in hand-to-hand combat deprived the rigid phalanx of much needed leadership which was detrimental in its battles against the manipular legion. While Roman generals did engage in personal combat with their troops, it was the exception rather than the rule. Most of the time consuls led from horseback just behind their battle line. This gave the commander an elevated position on the battlefield, as well as a platform from which they could move to sections of the field that needed their attention. An example of this is once again at the Battle of Cynoscephalae, where Quinctius Flamininus observed his left flank collapsing under the sheer weight of the Phalanx. At that moment, he decided he could be more useful elsewhere, and rode to his right flank, which proceeded to crush the unprepared and undeployed Macedonian left with his assistance. After that, another event occurred which shows the initiative of Roman captains compared to their Macedonian adversaries. As the majority of the Roman right flank chased the routing Macedonian left, a lone military Tribune managed to rally a significant number of legionaries to him and crashed into the seemingly triumphant Macedonian right - an action which won the battle for Rome.

This kind of action, where a small portion of a legion could act alone, was a uniquely Roman characteristics, and was rarely seen in the Phalanx which needed to function in as big a mass as possible to be effective. In the Roman Legions there was a high amount of command and control which was pushed down to the lowest ranks, a trait which is not evident in the Hellenistic militaries. The Roman centurion was an influential and powerful figure in the legion, and we see them taking their own initiative at Pydna to get their troops into the gaps as the phalanx opened up. We are also aware that senior Centurions participated directly in the consular leadership of a Roman army. As mentioned before, the Tribune at Cynoscephalae felt confident enough in his ability and authority without consulting his overall commander that he dispatched 20 maniples to the other flank to attack the enemy in the rear. Moreso, at Magnesia we not only see a Tribune rallying fleeing soldiers but executing those cowards who refused to reform. Those who did reform were led in a counter charge, all on the officer's own initiative. The conflict between the legionaries and the phalangites would continue, but the defeat of the successor kingdoms at the hand of the Roman state would prove that hands-down victory for the more flexible and intuitive legions over Alexander's Sarissa Phalanx.