What term describes political candidates that shift their positions based on public opinion polls?

The term that describes political candidates who change their positions based on public opinion polls is "waffling." This term implies a lack of firmness in a candidate's stance, suggesting that they are indecisive or opportunistic in their policies to align more closely with what the public currently favors. Waffling can create the perception that a candidate is more focused on gaining votes than on maintaining a consistent ideology or principle.

The other options do not accurately capture this concept. "Polling" refers to the process of gathering data on public opinion and does not imply a change in candidate positions. "Sampling" is a statistical term related to the selection of individuals for a survey but is not specific to political behavior. "Voting" refers to the act of casting a ballot and does not address how candidates might adjust their policies in response to public sentiment. Thus, "waffling" is the most appropriate choice for describing candidates whose positions fluctuate with public opinion.