Definition: Given a 'poster' sentence and a corresponding 'response' (often, from Facebook or Reddit)classify the sentiment of the given response into four categories: 1) Positive, 2) Negative, 3) Neutral, and 4) Mixed if it contains both positive and negative.
Input: Poster: We must stop the #omnibus. A vote for the omnibus appropriations bill is a vote to support unconstitutional surveillance on law-abiding Americans. How is your representative in Congress voting? #StopOmnibus #StopCISA  Responser: I was horrified during last nights debate. So many candidates calling for new levels of surveillance and bulk data collection. I fear for the future of privacy and civil liberties.
