How does domestic policy help the government fulfill its part of the social contract? Cite specific policies and link them to the purposes of government.

The idea of a social contract between a government and its people is predicated on the assumption that, when left without governance, humans tend towards anarchy, chaos, and violence—which are in no one's best interest. Based on this assumption, it is therefore beneficial to enter into a social contract, wherein certain rights are given up to a governing body in exchange for certain privileges, like protection. This concept is different than inalienable rights (which exist independent from any social contract), though it often includes some "rights" that aid in successful utilitarian governance.
A great example of this idea is the tacit agreement that individuals will not conquer land, owned or otherwise. Essentially speaking, all humans have the ability claim to the land around them; it is within their power to settle and inhabit this land, particularly uninhabited land. Obviously, this is a matter of ability—humans are capable of "conquering" their neighbors, but there is a moral or ethical question that arises from this action.
By agreeing not to act on this ability, and allowing the government to dictate what land is permissible for use and what land is restricted—either because it is owned by another individual or because it is protected by the government—an individual is engaging in a social contract. The government, in this way, then fulfills its obligation in this social contract by protecting the interests and safety of the society at large by sustaining this restriction; the government prevents someone from going out and claiming entire neighborhoods and cities for their own, as the citizens that inhabit these spaces have agreed not to do this.
There are many other examples of how the government protects the interests of society by regulating the communal sacrifice of certain "rights" or abilities (most notably the ability to use deadly force, which is punishable by law). In this way, the government fulfills its duty according to the social contract. Some individuals may argue that it is an infringement of "rights," but that is the very nature of the social contract: a relinquishing of "rights" in exchange for certain benefits.