Catholic social teaching is complex, linked with changing social conditions and deepening understandings of both the work of God in history and ethical principles. Nevertheless, this 
complexity can be summarized imperfectly in terms of seven key principles of Catholic social teaching. The following are highlights: READ FULL ARTICLE HERE
I. Respect the Human Person - The foundation for Catholic social thought is the proper understanding and value of the human person. In a sense, all Catholic social teachings articulate the ethical implications of a proper understanding of the dignity of the person. Each and every human being, as a child of God, has certain immunities from harm by others and merits certain kinds of treatment. In particular, the Church has been forceful in defending the right to life of every single innocent human being from conception to natural death.
II. Promote the Family - The human person is not simply an individual but is also a member of a community. Failing to acknowledge the community aspect leads to a radical individualism.
III. Protect Property Rights - Catholic social teaching has defended the right to private property against the claim that the state should own all things. Private property is essential to human flourishing.
IV. Work for the Common Good - only together as a community, and not simply as isolated individuals, is it possible to enjoy, achieve, and spread this good. All people are obligated to work towards making the common good a greater and greater reality.
V. Observe the Principle of Subsidiarity - Some Christian thinkers conceive of the state or government as being established simply to repress evil desires and evil people. In Catholic thought, the government also has a more positive role, namely to help secure common good. The government has many necessary and indispensable functions to play, roles that cannot be accomplished by individuals acting alone or even by smaller groups in society. The government should no intervene to attempt to alleviate all problems. A welfare or "nanny" state, offering cradle-to-grave security and attempting to provide for all human needs, expands the state beyond its proper scope and violates the principle of subsidiarity. All Catholics are obliged to work to find solutions to contemporary social problems in light of the Gospel and their best practical wisdom.
VI. Respect Work and the Worker - God not only creates man but puts him to work naming the animals and caring for the garden. Obviously, this task was not given to Adam because God was too tired to finish the job. Rather, human work participates in and reflects God's creative and providential care of the universe. Furthermore, workers are not mere drones, means to the production of capital for owners, but must be respected and accorded the opportunity to form unions to secure collectively a just compensation.
VII. Pursue Peace and Care for the Poor - Peace means more than just an absence of violent conflict. Peace is the "tranquility of order" in Augustine's phrase. War between nations may be necessary at times — but solely in order to restore peace. This just order of society also includes solicitude for the poor. Not only the direct or indirect effects of individual actions, but also wise social policies are necessary for a just ordering of society, social policies that must take into account the likely effect on the poor.
