The "junior senator from Wisconsin" was Joseph McCarthy, who was very bad news indeed. https://en.wikipedia.org/wiki/Joseph_McCarthy The First Amendment to the U.S. Constitution guarantees, inter alia, freedom of assembly (association). https://en.wikipedia.org/wiki/First_Amendment_to_the_United_States_Constitution So, the speaker is contrasting McCarthy's anti-democratic practices with the values and rights contained in the Constitution.

Hello! In my opinion "associate" here means to be connected to or to have something to do with the "causes that weren't popular" and so to challenge what is happening rather than to conform to what society expects them to do.

I agree with Lyn. I think there may be additionally the implication of associating with other people - i.e. spending time with other people and working with them - who have similar ideas. This is the use of the word as in the phrase "freedom of association".

Here associate means. To gather with, to be seen with, to be known as acquainted with. If something is associated with something then they are related in some way. For example flour is associated with bread when you think of flour you think of bread. With people you have business associates they are not partners necessarily, but they work together. In this context he is urging journalist not to be afraid of being associated with something. For example National Geographic magazine is associated with beautiful photography. A journalist may be associated with asking difficult political questions or with reporting on environmental disasters, or whatever topic it is that they are drawn to. Don’t be afraid of being associated with... , to be grouped together with..., to become known for.... The Alternative would be to be an average journalist who just reports the daily news with out their own take on it, with out putting their own personality into it and making it their own style. He is urging journalists to write in such a way that readers will know what journalist is writing just by the topic, writing style, word usage, etc. that they have become associated with.

I guess it should be communicate or accompanying