stalking horse
noun [ C ] uk/ˈstɔː.kɪŋ ˌhɔːs/ us/ˈstɑː.kɪŋ ˌhɔːrs/
（竞选中旨在分化对方力量或掩护己方主要候选人的）掩护性候选人
in politics, someone who competes for a position that they have no chance of winning, in order to divide the opposition to a particular group or to take attention away from another person who that group really wants to win.