I currently am studying for an MSc in international political economy and I also completed a BSc in economics. Political economy (as I study it) considers the ways in which markets and states interact, while economics entails a focus on how agents make choices in conditions of scarcity. For instance: Political economy may involve us asking "how can hegemonic stability theory and institutionalism help us understand the factors that led to the 2008 Great Recession?" Economics may involve us asking "what were the incentives bankers had prior to the 2008 Great Recession that helped cause it?" More on reddit.com

Economics is a political matter largely because people in politics won't stop messing with it. I'll instantly vote for anyone who runs on the platform of leaving me alone and not getting involved in my life. Let's call it the "Go Away Party." More on reddit.com

Marx uses this term because economics and politics are inextricably connected; one cannot be studied without the other. For detailed explanation see, Political Economy: A Beginner's Course By A. Leontiev. More on reddit.com

The general trend of science is that one does an analysis, makes predictions, the predictions turn out to be wrong in some way, so you realise that you don't truly understand the field you're studying. A classic example of this is from physics with the 1887 Michelson-Morley experiment that was intended to measure some of the properties of ether, which it completely failed at, this and subsequent experiments led to Albert Einstein's special theory of relativity. As Isaac Asimov said: The most exciting phrase to hear in science, the one that heralds new discoveries, is not 'Eureka!' but 'That's funny...' In economics, the stagflation of the 1970s was a case of people realising that the then-understanding of the economy was insufficient. The Global Financial Crisis another. As for political analysis this is indeed perfectly possible to do such analysis without properly understanding the economy. Lenin for example carried out political analyses before and in the early years of rising to power, about which he said, in 1921 : Partly owing to the war problems that overwhelmed us and partly owing to the desperate position in which the Republic found itself when the imperialist war ended—owing to these circumstances, and a number of others, we made the mistake of deciding to go over directly to communist production and distribution. We thought that under the surplus-food appropriation system the peasants would provide us with the required quantity of grain, which we could distribute among the factories and thus achieve communist production and distribution. In terms of understanding the economy, there's also some theoretical reasons to expect us to fail at it. In 1945, F. A. Hayek pointed out the importance of local knowledge that no central entity could ever master, such as knowledge of the temporary availability of spare cargo space, in 1976 Robert Lucas pointed out that it's naive to assume that past statistical relationships will necessarily hold if used for new policies as market participants will adapt their behaviour. On some of your other points: I end up confused and question whether I really have to understand something that is not possible to be fully grasped or tested. That's good, humility is important in science A rough test is to try to explain a thing to someone with no background in your field, if you can't explain it then you don't truly understand it yourself. but moral complaints will make themselves heard one way or another by those who are directly affected by them I think the main value of economics is learning to think not merely about the obvious but about the indirect effects of policies. For example there are many people out there who will justify horrible policies like colonialism or slavery on the basis that they benefited Western countries, but since the 18th century economies have been pointing out the losses of such policies. Another effect of economics is that some things that are commonly regarded as unethical, e.g. speculation, are regarded as ethical and valuable by economists. I'll also add that it's false to say "moral complaints will make themselves heard one way or another by those who are directly affected by them", for a start, dead people don't complain. Beyond this, there are serious issues of power in who gets listened to, even in democracies. For example median voter theorem predicts that democracies will give extra weight to the preferences of swing voters. To summarise, economics, like other sciences, proceeds by discoveries that prove our existing understanding wrong. In economics there are some specific reasons to think that our understanding will always be wrong in some way. However, economists have accumulated a lot of knowledge about how things can go wrong, and I think it's a bad idea to do political analysis in ignorance of economic theory. More on reddit.com