Why Does Dealing with the Policy Challenges of Medicare and Social

Why does dealing with the policy challenges of Medicare and Social Security create a prisoner's dilemma?

A) The benefits awarded by these programs are not regulated in any way, so seniors consume a large share of the federal economy.
B) The transaction costs of reaching a deal are high because there are so many actors who will want to be involved.
C) Finding a focal point to start the discussions is a very real challenge and with neither side knowing where to start the conversation.
D) Each side knows that they could benefit from reaching a landmark entitlement reform deal if they could just trust the other side to cooperate.