What idea did john locke advocate for the role of a government

To be the protector of natural rights

Explanation:

According to john Locke, every citizens had a set of inherent rights that cannot be violated even by the government ever since we are born, we call this set of rights as our natural rights (this rights include things such as the right to live, the right to liberty, the rights to obtain private property, etc)

He argued that government should play a limited role in society, and protecting the natural rights and maintaining national security belonged within that limited role.