The Non-Aggression Principle, sometimes referred to as ahimsa, is in its modern conception the idea that each person has the right to make their own choices in life so long as those choices do not involve the initiation of force or fraud against others.
Antecedents to the Non-Aggression Principle can be found in the writings of historical figures including Frederic Bastiat and Thomas Jefferson and going as far back as the legendary Chinese sage Lao Tzu. In more recent times, it was more formally articulated by thinkers such as Albert J. Nock, Ayn Rand, and Murray Rothbard.
The Non-Aggression Principle is widely considered to be the key foundational principle of the political philosophy of libertarianism, and a version of it can be found in the pledge which members of the U.S. Libertarian Party are required to sign in order to vote or hold office within the party.