The problem with this article is it does not GIVE US THE REASONS as to why the Professor makes his statement. It just presents his blanket statement without telling us why he believes it is so...
9-9-9 for example, is designed to reach a solution rather then get votes. If it were designed to just get votes, there would be no sales tax. Instead Cain would simply continue what the professional politicians are doing and promise his plan would allow them to have all the Government spending they want and they would not ever pay for it.
In other words if all they wanted to do is "get votes", the GOP Candidates would all adopt the Democrats tax plan. Give citizen A-B-C and D stuff from the Goverment make citizen E-F and G pay for it.