Jon Huntsman has quit the 2012 Republican presidential race with a call for candidates to cease personal attacks, often conducted through shadowy campaign vehicles known as super-Pacs.
These political action committees, which are transforming the nature of the US presidential races, can raise unlimited campaign contributions, so long as they spend the money without co-ordinating with the candidates they are backing.
However, the huge sums spent by the super-Pacs and the close ties between their operatives and the candidates have fuelled public cynicism about politics.
您已閱讀38%（572字），剩餘62%（916字）包含更多重要資訊，訂閱以繼續探索完整內容，並享受更多專屬服務。