. >> the author of princeton university professor keith wailoo. how do you write a political history of pain. >> guest: that's a wonderful question. so, my background into the hoyt of medicine and i've always been perplexed by the fact that we have such a hard time treating people in chronic pain in america. that is to say debates about whether too much medication promotes drug addiction how to measure pain, not something that is easy, but what i realized is a started to do the research on why this area of medicine has been controversial is how it intersects with deep and divisive issues in american society. about how you measure pain. how too you decide who is in pain and who is not. the story really becomes highly politicized way before the 19 -- today it becomes politicize nets '50s when we establish a disable provision in social security in 1956. eisenhower era. and the question before physicians is, okay, we know what a disable looks like but is pain a disability? is chronic pain something that is not easy to measure, a disable that should be