Decades of participation research show that political activity increases with income, but the participation of senior citizens specifically with regard to Social Security poses an exception to this pattern. Social Security-oriented participation decreases as income rises, in part because lower-income seniors are more dependent on the program. The negative income-participation gradient is especially pronounced for letter writing about the program, but even Social Security-related voting and contributing are less common among higher-income seniors. This is an instance in which self-interest is highly influential: Those who are more dependent are more active. It is also an example of lower-class mobilization with regard to an economic issue, something quite unusual in the United States.