Here’s a quotation from Mill’s Principles of Political Economy that modern economists should take to heart:

For practical purposes, Political Economy is inseparably intertwined with many other branches of social philosophy. Except on matters of mere detail, there are perhaps no practical questions, even among those which approach nearest to the character of purely economical questions, which admit of being decided on economical premises alone.

Perhaps one of the many consequences of the Great Financial Crisis will be the welcome revival of Political Economy.