Washington Post and ABC News have done a poll checking out whether people had a favorable or unfavorable attitude to 9-9-9 and a flat tax plan. Among Republicans, 41 percent had a favorable view of 9-9-9, while 50 percent had an unfavorable view. Poll the entire population, and the reaction is 36 percent favorable and 56 percent unfavorable.
Regarding a flat tax system (one important distinction: Rick Perry is proposing a plan that has an optional flat tax, not a flat tax that would absolutely apply to everyone, as the poll questions seemed to suggest), 56 percent of Republicans view it favorably, while 41 percent have an unfavorable reaction. Among the population as a whole, 47 percent viewed it favorably and 48 percent viewed it unfavorably.