I've found this treaty:No idea. I'm not sure Sanders really has a solid foreign policy, I like him for his domestic policy. What was the name of the agreement?
http://isap.sejm.gov.pl/Download?id=WDU20050030014&type=2 (bilingual version)
I perceived Americans as those who popularized such investment protection treaties, so I look a bit puzzled when they are unhappy about them... ;)
(Our foreign affairs ministry mentions that already signed regulations concerning investment protection in US-Polish relationship are broader than the ones from TIPP, so no big problem...)