Straddle the fence is a common idiom that means someone is unable to make a decision or take a side in an argument or situation. There are plenty of synonyms available that can be used in place of straddle the fence include sitting on the fence, being wishy-washy, being undecided, being noncommittal, being ambivalent, being hesitant, being indecisive, being neutral, being on the fence, being unsure, and so on. Each of these synonyms conveys the same meaning as straddle the fence and can help in conveying the message more clearly. So, the next time you want to express someone's indecisiveness, use one of these synonyms instead of straddle the fence.