During the rather bitter 2004 Presidential election I recall reading what I considered to be a rather wise and somewhat non-partisan article. Unfortunately, I forgot who wrote it and where it appeared (I believe it may have been The Wall St. Journal, which admittedly leans a bit to the right) but the writer stated that the acrimony that exists between those on the right and those on the left is largely due to those on the right-- whether they realize it or not-- having an air of moral superiority and those on the left having an air of intellectual superiority.
To put it a bit more bluntly it comes down to whatever those on the left say, the people on the right hear, "If you don't agree with me you're a stupid boorish cad. I feel sorry for you, but it's okay I know what's best for you." And no matter what people on the right say, many on the left just hear, "You are immoral heathen scum but we can help you save your soul."
I'd have to agree with the author of the article in that until we can get past our conceits and really admit we have those conceits about our own beliefs we won't be able to actually discuss WHY we believe what we believe. We'll just keep getting stuck fighting over why our beliefs are right and those of the opposition are wrong.
If people actually sat down and discussed respectfully and civilly the reasons and motivations behind their beliefs and why they have the beliefs they do we may be surprised to find a bit more common ground than we might otherwise have thought.
One of the best teachers I ever had, a high school history teacher once said that the fringes legitimize the middle. The trouble is that both parties have allowed the fringes to become the mouthpieces of their respective parties and thus created further division and acrimony. I'd argue that most Americans are moderates. Yes we lean a bit to the left here and a bit to the right there but for the most part our beliefs and ideas aren't too divergent from each other.
The Articles of Confederation which predated our Constitution were rigid and in order to effect change the unanimous vote of representatives of all 13 states was required. Our Constitution was born out of the failure of that rigidity. It was born out of compromise.
But now, guided largely by the rigid and unflinching voices of the extreme left and right our elected officials have largely forgotten the lost art of compromise. In letting our own worst elements and most divisive voices guide us a general air of acrimony has festered and grown. Yes, it is largely a product of the Internet which has allowed those on the fringes to gather and organize and thus amplify their voices. But the fringes have to amplify their voices because they're in the minority. Unfortunately this creates the false perception that they aren't the minority but the majority-- that these people hold the prevailing opinions of our two respective parties. And this false perception only feeds that acrimony and creates an ever growing ever more vicious cycle.