In many ways, we were a nation built on diversity. "United" does not mean being of the same beliefs, morals or even prejudices. One of the primary things we must be united in is to keep this damn thing glued together despite our differences.
Humans will always suffer from a wide variety of character flaws and none of us even approach perfection. I must be willing to accept that many Americans will always hold on to their prejudices, hatreds, spite, immorality, racism, and even outright stupidity. However, I must also hope we all - with time - outgrow the worst of these flaws. In my 70 years, I've watched us very slowly improve in many of these areas.
Just stop and look back at our history - even as rotten as some parts are - and how the nation was built by a huge variety of people of various nationalities, ethnic background, social and economic status, etc. I also remind myself frequently that for many years, I worked jobs all over the USA with a tremendous variety of hard working folks, and very rarely was politics discussed, and no divisiveness was felt. We simply stayed focused on the task at hand, talked about families and fishing, and shook hands at job's end.
We currently have a very large number of wealthy people and foreign interests and assets that want nothing more than for us (the commoners, if you will) be divided and at each others throats every day. And, social media and an irresponsible press are making things much worse and amplified. We must try to be united in fighting these very evil forces in every way we can, or they will eventually destroy us.