The Five major reasons why we could find polarization in US:

Community:

The American community consists of so many different people, which made it to be under the term of polarization. These differences in the community lead to a different ideas, logical views, and even in the way they look at to each other. This collection of the people (white and black, different religious sides, political tendencies …etc.) leads the people to be in as opponents and the outcome is the polarization.

Immigration:

It may consider one of the most important factors in making collections in side any community. The immigration from different countries brings different ideas, new political theories, opinions and new social views. So, Immigration leads to establish so many sides inside the one community each side represent a theory, group of ideas and different way in tackling with the matters.

Media Polarization:

Media is an important section in the life now a day which should represent the people as a whole, but unfortunately it serves the side that supports it. It is always in the side of these political sides that it serves which may be who made this channel and who is responsible for spending money on it. So the job of the media may exceed only polarization to reach to a fact that it may be one of the factors that works for increasing polarization inside the community. Its dangerous way through out what it spreads and broadcasts to the people and it surely serve one side and getting out the main purpose that it made for which is  to serve the people not to serve one political side. So we have to be careful from such a kind of media because it may cause a war between the people and not only polarization.

Economic:

Also economic plays an important role inside the community and with the idea of polarization. Some of the communities have two economical sides either too rich or too poor and that what we see in America that there are so poor people and so rich people and the level which is in between represent a low rang compared with them. So the rich will represent a side which is the controlling one but they are little in number compared with the other side of the poor people who are large in number but without any powers which is the power of money. So this harsh treatment to the poor people leads to a serious polarization.

Political fragmentation elite:

US is showed their political parties in two major sides, they are the Democratic Party and the Republican Party with a third minor side. That leads to separate the sound of the people into two major sides and lead to a real polarization.