AIDS research, rights for people with disabilities, health information technology, abortion clinic access - there is hardly an issue in the health care arena he has not touched. Some on the left remain optimistic, despite this summer's backlash against their health care proposals. [...] Ron Pollack, executive director of Families USA, said they will have Kennedy to thank - for inspiring his colleagues, for persuading President Obama of the importance of prioritizing health care, and for working behind the scenes in his last days.