Contemporarily, political economy refers to different, but related, approaches to studying economic and political behaviors, ranging from the combining of economics with other fields, to the using of different, fundamental assumptions that challenge orthodox economic assumptions. [Wikipedia]
Historically, Political Economy referred to what we today would regard as Economics, and most early economists, from Adam Smith to Karl Marx, conceived of their study in those terms. But economy and political divorced in the late 19th century, rendering the illusion that Political Science and Economics are approachable distinct from each other.
To put it mildly, current events reveal that that divorce is a mistake and that political and economy must remarry.