The enduring issue is the ongoing debate and conflict surrounding economic inequality and the quest for a fairer distribution of resources and power within societies which can be seen in the ideas of Adam Smith, Karl Marx, and Vladimir Lenin. rephrase like a 9th grader same word length

The ongoing problem is the never-ending argument and fight about how money and power should be shared fairly in societies, which is shown in the thoughts of Adam Smith, Karl Marx, and Vladimir Lenin.