This study examines the effect of inoculation as a strategy in competitive framing in the context of public opinion about taxes on sugar-sweetened beverages (SSB). Inoculation is a theory of resistance to persuasion which suggests that by exposing an individual to a weakened form of an oppositional message, individuals can develop counterarguments to resist future exposure to oppositional messages. Researchers conducted a two-wave longitudinal framing experiment examining the impact of exposure to several combinations of pro-tax frames, anti-tax frames, and inoculation as a counterframing strategy, relative to no-exposure control groups. The inoculation message identified soda companies as the main opponents of SSB taxes, described their action and motives for framing the issue to their advantage, and used strong pro-tax frames to refute anti-tax frames. Survey respondents were asked about their support for SSB taxes and beliefs about negative soda company practices. The study found that respondents exposed to an inoculation message held more favorable opinions of SSB tax policy immediately after exposure than those in the control group, but exposure to strong oppositional frames at follow-up canceled out the initial persuasive effects of the inoculation message and thus failed to produce a net increase in policy support.