"The Democrats are the party that says government will make you smarter, taller, richer, and remove the crabgrass on your lawn. The Republicans are the party that says government doesn't work and then they get elected and prove it." ~P.J. O'Rourke
That's pretty much it in a nutshell. Both political parties are more concerned with demonizing their opposition and getting out of context sound bites. Create a straw man argument, then a caricature of your opponent, then proceed to run against both as best you can. Republicans are far better than this than Democrats but both manage to bring out the worst in their fringe elements every election cycle.
It's come to the point where we are a country of people against each other. It's the politicians, the major corporations who donate to them and the media who can't pass up a chance to sell more ad time that have us convinced that our next door neighbor could be unpatriotic for supporting one idea or another. There's no real, productive debates any more, just name calling, posturing and game playing. More than ever, it makes sense to have a 3rd party with no corporate donations and no special interest since neither party comes close to really representing the sane people that vote for them. The fringe elements and special interests of both parties usually end up controlling who is on the ballot, not the reasonable people who compromise and engage in bipartisanship instead of trying to ram their ideas down the throat of an unwilling country.