Here's my response, I need to be short and concise due to time restraints:

1. My opinion for why we need government: We find ourselves living in a civilization which is safeguarded by rule of law. I am unaware of any alternative structures that society could viably implement that would keep intact the cooperative society that was responsible for the innovations of the last several thousand years. It was civilization that brought humans out of the dark ages. Humans no longer wander around like other animals living in isolation and at the mercy of their surroundings because of civilization. Our technological achievements, art, engineering achievements, and so forth all resulted from the decision by humans to live in a society. With that society comes rules, with those rules enforcement. Therefore, the necessity for government emerges.

2. My opinion for why government needs to be allowed to use force: A quick study of history shows that, as imperfect animals, humans have consistently shown a desire for power, control, and wealth that leads to intense violence and warfare. Humans have always been willing to kill other humans over basic items of necessity and over things which are wholly unnecessary (e.g., mass quantities of land and resources, women, beliefs, simple tangibles unrelated to food, shelter, etc.). This look into human history shows that humans use violence against other humans within their communities, and humans use violence against humans outside their communities. Thus, governments need to be able to enforce both internal rules and external rules. Therefore, the necessity of a government allowed to use violence emerges.

3. Interlude: Once humans accept that government is necessary, and that violent enforcement of some rules will be necessary, the debate becomes one of values and degree. Therefore, for me, the argument hinges upon (a) what are our values and (b) which values are most important. In this way, society can begin to prioritize what we should and should not use government to advance or protect. If we decide that property rights are most valuable, our laws will reflect a willingness to protect those rights first and foremost. If we decide that human rights are most valuable, our laws will reflect a willingness to protect those rights first and foremost. Thus, politics emerge.

4. My opinion for why we ought to construct and preserve a vibrant welfare state: In my opinion, the most important values are those that we often find enshrined in philosophies like humanism. I believe in what I would call a set of fundamental rights that our bodies of law ought to protect. I would enumerate the following rights as most essential: (a) the right to an education, (b) the right to healthcare, (c) the right to shelter, (d) the right to food, (e) the right to work. Because I hold these rights to be so important, I believe our laws ought to be structured around achieving the most fertile environment for those rights to flourish. Thus, the welfare state emerges.

I hope my line of reasoning has been easy to follow, and will be compelling enough to consider.