I'm surprised that more people haven't railed on this. Political economy is an academic subfield that is central to current American political science and is at the forefront of most modern scholarly research in economics. You don't have to be a Marxist to think that political economy is a vibrant sub-discipline of the social sciences, nor is political economy limited to the analysis of land, labor, and capital.
Some snippets of the types of things that political economists write about:
The political economy of regulation. When is regulation feasible? What types of interest groups are most successful at obtaining government regulation of their industries?
The political economy of liberalization. In what cases does the political system of a country determine its willingness to open itself to the global markets?
The public economy of states. What determines the size and composition of a state's budget?
The "electoral-economic" connection. Do governments manipulate fiscal or monetary policy when facing elections? How often, and under what conditions?
Globalization. Is globalization good or bad for economic development, inequality, and/or political particpation? Does the political system of a state determine the effects of globalization?
Macroeconomic policy. Does the political system of a state determine the autonomy of that state's central bank and its ability to make prudent policy choices? When central banks are not autonomous, what happens to macroeconomic policy?
All of this falls under the heading of "political economy." Interestingly, for those who insist that American institutions are guilty of ignoring other points of view, the oldest scholarly journal published in the United States in the fields of political science AND economics is entitled the "Journal of Political Economy." It is also among the most respected social science journals around.