Megan McCardle on the debt-ceiling deal and the coming civil wars within the parties.

Within the Democratic caucus they will have to choose between old people and poor people. Republicans will have to choose between tax increases and a strong military.

Me, I'd like a single entitlement system that takes care of people who are actually destitute and unable to work, not this mad scheme whereby America's middle class is supposed to get rich by picking its own pockets. You, dear reader, probably have other ideas. But whatever your ideas, you cannot assume the voters away. They are going to get in the way of your quest for the ideal world. So parties are going to have to start thinking about which constituencies they want to sell out in order to preserve the important core.