Will social security and Medicare remain viable as the U.S. population is aging?

Yes, subject to concerns about Medicare cost and potentially self-confirming skepticism. The U.S. social security system (broadly defined, including Medicare) faces significant financial problems as the result of an aging population. But demographic change is also likely to raise savings, increase wages, and reduce interest rates. Viewed in this context, the fiscal problems of retirement insurance seem over-rated. A more serious issue is the rapid growth of Medicare spending. Up to a point, a growing GDP-share of medical spending is an efficient response to an aging population. But Medicare growth might be excessive due to moral hazard problems. Except for this caveat, social security is almost certainly economically viable. To examine the political viability of social security, I focus on intertemporal cost-benefit tradeoffs in a median-voter setting. For a variety of assumptions, I find that social security will retain majority support. I also discuss the role of altruism, redistribution, and multi-dimensional voting and find that they provide additional voter support for social security.