Exile and Immigration

The United States is the "land of opportunity." We are the wealthiest nation in the world; we have the most available natural resources and the technology to access them. As a whole, Americans believe in education for our children, accessible healthcare for all people, shelter and food for everyone, and the freedom to worship as one pleases. If you live in the USA, you can be anything you want to be, regardless of your social, economic, or racial status. Opportunities and resources for success are available for those willing to work hard. In a nation that thrives on captialism, anyone with heart, hard work, and imagination can live well.
But as Americans, we also know that not everyone in the world lives like we do. Many people in the world struggle just to put a roof over their heads and food on the table. Many people live in places where, for various reasons, basic needs are not available; places where abject poverty is the norm. For people who live in the midst of war, of famine, of government tyranny, of religious oppression, life holds very little opportunity. For those who have been exiled from their homes and countries because of forces beyond their control, or for those who have left their homes and their countries to seek something better for their families, life can be a state of isolation.
It is a fact that people from all over the world seek refuge in the United States. People come to the US looking for a better life, a life that can bring them happiness instead of despair, hope instead of hopelessness. Sometimes, the opportunities to be found in the US cannot be found anywhere else in the world, so displaced people come here to take advantage of those opportunities.
Immigration is a big issue in the United States right now, and will be a big issue on the Presidential platform for all candidates in the coming year. Taking into consideration that some immigrants are here legally, that some immigrants simply want what we all want, i.e., happiness and security, that some immigrants have been displaced from their own lands because of factors beyond their control, what do you think should be done about immigration? Does the USA, as the wealthiest nation in the world, have a responsibility to open its borders for those seeking refuge from war, poverty, and other factors? Does the USA have a responsibility to care for those who come to our land for hope?