the civil rights movement is one good example. the pressure put on FDR with regard to federal jobs. the military. i am too lazy to unearth the book, but i read Deborah Gray White's history of the black women's club movement, which gives you a backroom look at what went on -- the internecine warfare among black women and black men -- involved in the civil rights struggle. but one thing is clear there, it was the enormous pressure of a social movement that made anything happen in terms of government policy.
and the interesting thing, in terms of the military (i've completely blanked out on the research authors i was reading) integration has had a huge effect on decreasing anti-black racism in those environments. precisely because, as miles is always saying, the pressure for social change from blacks forced the government to make institutional changes and this, in turn, changed people ideas. when i remember the name of the research i read, it was about the area where i'm currently living, i'll post it. sorry for not remembering right now. but it was based on comparative research on racist attitudes, beliefs, actions, and violence in military towns.
oh! and feminist social movement had a big effect on affirmative action policies. I can witness with my own life the difference between when I was sexually harassed in college by a professor, where the entire department knew that was his yearly habit, and literally did nothing about it, to now, when that kind of thing wouldn't be tolerated. i could tell a similar story about attempted rape by a guy taking me home from babysitting his kids. but will spare the details. suffice it to say, i don't think, today, many cops would have turned the blind eye they almost did then. almost -- because, even though cops seemed to be condoning his behavior at the time, i screwed up my courage and figured (hoped) i was safer with the cops -- even though they acted as if he'd done nothing wrong.
thus, i'd say that anti-rape activism and anti-domestic violence activism changed the way police handle domestic violence. rape rates have declined -- especially in terms of stranger rape and rape of women in their late 20-40s.
there was also the poor people's movement though the results are ambiguous there.
also, the way that births are handled, completely different because of the feminist movement. that change happened in the short span of a decade. not government policy, no, but it's worth noting since you don't always have to go after government social policies to make small improvements in people's daily lives.
shag