I have read everything he ever wrote plus all of the biographies, etc. I would say that he expressed a libertarian streak in many of his books but he started out as a socialist and Democrat in the 1930s (Upton Sinclair).

I think more than anything else, he wanted the state to stay out of the way of people exercising individual agency. He felt that people should act like adults and conduct their own affairs and work things out individually. He frowned on morality police and despised the false sanctimony of organized religion.

He was well aware of the creeping totalitarianism inherent in giving the state too much power and in "Friday", one of my favorite books from his late writing period, he is not kind to California in terms of describing the political situation. IIRC, he mentions excessive taxation as a serious problem (quite prescient as it turns out). He hated bureaucrats and pompous politicians and many of his protagonists lived in armored or secured compounds due to the degradation and corruption of civil order.

A common theme in several books is that when a society gets to the point of requiring ids, liberty becomes a casualty. I think he chafed under the restrictive mores of his era and dreamed of a freer society.

On the other hand, in "For Us, the Living" (written in '38 but published posthumously in '03) I just listened to a scene where the protagonist, who time travels forward 150 years from the 1930s, is sent to be re-educated because he punches someone out of jealousy. Violence is not allowed and psychiatrists are called in to correct his atavistic behavior. No one questions the right of the state to brainwash the protagonist. Conformity to custom is enforced by law.

So, I would say he flirted with quite a few ideologies over the course of his writing. Regardless, I credit him with expanding my universe on a multitude of vectors. He is the first writer who challenged me to think about systems - in terms of governments, infrastructure, and the ways that societies organize themselves. He also made me think about what it actually means to be and live as a free person.