i would like to say you could trust missy franklin you could trusts michael phelps. we all know, we were born here, not born yesterday. i'm not saying michael phelps or missy franklin, but, bad chemical is are way ahead of the good chemical is in -- chemists. >> the authorities haven't begun to test for because they don't know exist that these athletes may be taking. this is a devastating blow when mr. clean the guy who stood up there and said i am clean has tested positive and the jamaicans as well. i'd like to say there's some hope but tougher testing has got to be the answer and athletes who decide they can't cheat anymore. >>ifill: christine brennan, thank you so much. >> gwen, thank you. >> woodruff: finally tonight, to mexico, and a personal look at our country's neighbor to the south through the eyes of a journalist. margaret warner has more. >> warner: mexico is a country of riches and promise, now the second fastest-growing economy in latin america, and it is plagued by violence and corruption fueled by the drug trade that has killed some 80,000 people in th