Xi later gained a doctorate in Marxist theory from Tsinghua.

The party sought to attach Marxist theories to populist rhetoric thereby catering to the disenchanted masses.

I've read enough Marxist theory to feel that such a view may be a reactionary way of looking at things.

Before long he had surpassed his comrades in Marxist theory and rhetoric and caught the eye of the youth-movement leaders.

He fell in love with her, despite her arguing with him about Marxist theory; wanting him to get to know the masses, etc.