Here it is: Meaning of the Phrase 'Provide for the Common Defense'

Meaning of the Phrase 'Provide for the Common Defense'
One of the most well-known parts of the US Constitution is its Preamble. Historyplex explains the meaning of one of its phrases - 'provide for the common defense', with its definition and other facts.
Written in Stone!
The Preamble is the only part of the Constitution which can't be amended (changed), because it explains the purpose of the Constitution.
The US Constitution is a carefully-worded compromise between different states. This was vital for the document to be approved, since it had to satisfy the members of every state legislature who had their own expectations from it. Since each part of the Constitution had to pass heated debates in Congress and the states before it was approved, every word in it has the right place and meaning. However, for the common public, such a technical document can be difficult to understand. One of its phrases which has caused a lot of confusion among readers is 'provide for the common defense'.
Provide for the Common Defense: Meaning
This phrase means that the protection of the United States, its citizens, and property, is the responsibility of the federal government, and not of individual states.
Where is this Phrase Found?
This phrase appears in the Preamble of the US Constitution. The Preamble is an introduction which gives the reasons why the Constitution was formed. Courts do not use it in their daily functioning to interpret the laws or powers of the government.
How is Common Defense 'Provided'?
❑ Article I of the Constitution allows Congress to raise a national armed force, and collect taxes for this purpose.

❑ Article II gives the President the right to serve as the Commander-in-chief of the armed forces.

❑ The armed forces of the United States has a long history of protecting the country against all threats.

❑ The Department of Defense helps the forces carry out military actions against foreign threats.
❑ The Department of Homeland Security deals with any threats to internal security, like terrorism and natural disasters.
Original Source of the Phrase
The phrase was copied from the Articles of Confederation, which was the first Constitution of the United States during its initial years. While the Articles attempted to make the federal government responsible for the security of the entire nation, it failed to achieve this. So, the Framers of the new Constitution decided to make it a key objective.
When the United States became independent in 1776, there was no common army or navy for protecting the whole country. Until this time, each of the 13 states were responsible for ensuring their own security, for which they had formed state militias (citizens' army). Each state had contributed its own militia, thus forming the Continental Army that fought the British. However, changed circumstances made a common military for the country necessary.
A strong army would facilitate the withdrawal of the remaining British troops from the Western border. Moreover, the presence of a navy would prevent the Spanish from closing off the Mississippi river for US trade, preventing damage to the latter's interests. Around the same time, US merchant ships began to be seized by North African pirates in return for tributes.
The Framers of the Constitution realized that a common armed force was necessary to protect the sovereignty and interests of the United States, especially with increasing conflicts with the Natives. However, they were wary of a standing army (permanent army), as such armies had been used by European monarchs to oppress their subjects.
While giving Congress the power to raise an army and a navy, the Framers restricted its power to fund such an army to only two years. While ensuring the security of the new nation, this rule prevented a permanent army during peacetime.
The phrase 'provide for the common defense' indicates one of the reasons why the independent states decided to unite as a country - so that they were protected by a unified military, rather than guard themselves independently.