Carrol: you're on the money about the CP's role in the civil rights movement, but not in the anti-Vietnam War movement. there the big old left party was the SWP. jks
The SWP pushed for the right slogan (Bring the Troops Home Now) and they were certainly the most important force in organizing the huge anti-war rallies of '68 and thereafter. But CP or ex-CP cadre were of great importance in many localities, and they contributed to the mass rallies. Red-diaper babies were pretty important in SDS.
There were of course other important factors in both movements than the CP or SWP -- but it is really stupid to cut ourselves off from our history as many stalin-baiters do. Whatever one thinks of Stalin (or Trotsky) himself or of the Comintern, the masses of people in and close to Third International parties were the center of progressive action and thought for many decades. The world would be a poorer place but for their struggles. Just as it is a poorer place because of the fall of the USSR (and the return to capitalism of the CPR).
Carrol