My wife and I try not to get into political discussions with other people, unless we're confident it can be a rational, fruitful discussion. Our views are roughly in the same zip code and generally place us in "small-L" libertarian territory.
There are some people that we just don't talk to any more, because they've gone so far off a deep end (most of them off the left side) that you just can't deal with them. And most of them (we assume, from knowing them before) are not stupid people, which makes that all the more puzzling.
Also, my wife especially avoids talking politics with a lot of people, because large portions of her social and quasi-professional relationships would be shocked, appalled, and essentially horrified that someone they know and like would fall outside the party lines. Apparently in many social/demographic groups, there is a lot of pressure to conform and toe the party line, and no dissent is tolerated. Anyone who doesn't either keeps it very quiet, or is largely ostracized.