an occasion in which you vote for a political party or person that you would not usually support in order to prevent another party or person from winning

They gained in the election by attracting tactical votes against the Tories. 他们通过吸引反对保守党的策略选票而在选举中获胜。

There is no doubt that the tactical vote strategy was operated by some voters. 有些选民无疑选择了策略性投票。