Consider change over time, are there groups working toward ameliorating the bad? Are public policy changes taking place, even if at a slow pace? Or is nothing being done? Admitting injustices while discussing efforts at reform may be enough to sway someone to your side. one way to organize would be along the lines of first discussing domestic socio-economic issues, followed by domestic political issues, and finally foreign policies in the era under discussion. Remember that each of these elements of the overall argument would have its own paragraph and thesis this is a real-life situation, there was a fight for the hearts and minds of the world. The cold war is an ideological (and sometimes hot) battle over two socio-economic/political systems and 1970 is in the heart of the cold war. Who will be the victor was not yet clear. Most of the third world nations courted by the United States were not European; therefore how the us treated minorities would be a cause for concern. But these nations would also have very real geopolitical considerations beyond American domestic policy to consider. The soviet propaganda was meant as a wedge. Also remember that no nation or society is perfect, that is not what you are arguing here. In your persona as a diplomat from 1970, you are giving an honest assessment of the us, warts and all, in hopes of gaining an ally.