Kerry and Carson didn’t write their letters for the “43 other countries”.
I am not saying that CODEPINK is the biggest and the most influential, but they did a lot during the 2008 Presidential election. Raised a lot of money and influenced a lot of votes. I understand why you would want to put some distance between them and the Democratic party as she descends further into the anti-zionist/anti-Israel pro-terror world.
Again, my point is that she is not just some nameless activist. She, and her group are serious players.