Who Said If You Want Peace, Prepare for War?

This Roman idea is still in many minds today.

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The original Latin of the expression "if you want peace, prepare for war" comes from Epitoma Rei Militaris, by the Roman general Vegetius (whose full name was Publius Flavius Vegetius Renatus). The Latin is: "Igitur qui desiderat pacem, praeparet bellum."

Before the fall of the Roman Empire, the quality of its army had begun to deteriorate, according to Vegetius.  The decay of the army, according to Vegetius, came from within the army itself. His theory was that the army grew weak from being idle during a long time of peace, and stopped wearing its protective armor. This made them vulnerable to enemy weapons and to the temptation to flee from battle.

The quote has been interpreted to mean that the time to prepare for war is not when war is imminent, but rather when times are peaceful. Likewise, a strong peacetime army could signal to would-be invaders or attackers that the battle may not be worth it. 

Vegetius' Role in Military Strategy

Because it was written by a Roman military expert, Vegetius' Epitoma rei militaris is considered by many to be the foremost military treatise in Western civilization. Despite having little military experience of his own, Vegetius' writings were highly influential on European military tactics, particularly after the Middle Ages.

Vegetius was what was known as a patrician in Roman society, meaning he was an aristocrat. Also known as the  Rei militaris instituta, Vegetius wrote Epitoma rei militaris sometime between 384 and 389 C.E. He sought a return to the Roman military system of legion formation, which was highly organized and depended on a disciplined infantry.

His writings had little influence on the military leaders of his own day, but there was a particular interest in Vegetius' work later, in Europe. According to Encyclopedia Britannica, since he was the first Christian Roman to write about military affairs, Vegetius' work was, for centuries, considered the "military bible of Europe." It's said that George Washington had a copy of this treatise. 

Peace Through Strength

Many military thinkers have modified Vegetius's ideas for a different time. Most modified the idea to the shorter expression "peace through strength."

Roman Emperor Hadrian (AD The Roman Emperor Hadrian (76–138 C.E) is probably the first to use the expression. He is quoted as saying "peace through strength or, failing that, peace through threat."

In the United States, Theodore Roosevelt coined the phrase "speak softly, but carry a big stick."

Later, Bernard Baruch, who advised Franklin D. Roosevelt during World War II, wrote a book about a defense plan entitled "Peace Through Strength.

The phrase was publicized widely during the 1964 Republican Presidential campaign. It was used again during the 1970's to support the construction of the MX missile.

Ronald Reagan brought Peace Through Strength back into the limelight in 1980, accusing President Carter of weakness on the international stage. Said Reagan: "We know that peace is the condition under which mankind was meant to flourish. Yet peace does not exist of its own will. It depends on us, on our courage to build it and guard it and pass it on to future generations."