Why does politics bring out the worst in us?

I have been a registered republican for at least 25 years and nothing you are saying is new. My sister (the die-hard democrat) said she was appalled when Elisabeth Helbeck from the View said she would support our new president. My sister found this honest patriotism disgusting. I said, if McCain had won, Helbeck would have said the same thing, and my sister would have said she must think we are dumb. Democrats think patriotism and cooperation for the good of the country is stupid. It isn't politics that brings out the worst in us, it is liberal idealism. If Obama is different (as his rhetoric suggests) I will be thrilled. But what party is going to go along with him? Not the democrats in congress.