The Green mayor of the German city of Tübingen, Boris Palmer, announced his intention to run for re-election as an independent candidate on Sunday, following a furore over his use of racist language. The regional Green party leadership voted in May to launch an investigation into various comments Palmer had made on subjects including race and migration that departed from the usual party line. Palmer made a Facebook post earlier in May about German football player Dennis Aogo, in which Palmer used a racist term to describe the black player. Palmer claimed that his statement was meant to be iron…