By relying on a system that funded old age pensions through a regressive tax on wages, SS fosters the idea that everyone who has paid has a moral right to withdraw at a later date. Voegeli quotes FDR as saying:
We put those payroll taxes there so as to give the contributors a legal, moral and political right to collect their pensions and their unemployment benefits. With those taxes in there, no damn politician can ever scrap my social security program.Further, the SS administration aggressively marketed the program in order to convince Americans that this was really an insurance program with premiums and "accounts". After selling this long enough Americans came to believe it to be so.
A perfect example of this is my father. He's pretty consistently conservative on political issues. But when it comes to SS he's one of the converted. Having lived his whole life with the program it's just part of the world that he accepts. While he agrees that there are financing problems and would be willing to raise the retirement age to address them he reflexively opposes any significant changes. It's almost a matter of faith that SS will and must continue to operate the way it has for sixty plus years.
I'm no great fan of FDR's New Deal policies. I've made the comment, somewhat hyperbolically, that the Great Depression was the worst thing that ever happened to this country because of some of the changes in our government that arose as a result. But I have to admire the tactical political genius displayed by Roosevelt and his administration in pushing through these changes and so skillfully ensconcing them in the American consciousness.