Here are many images for this particular set of search terms (freedom of speech):
I found them by going to http://images.google.com and entering the phrase.
Now you can also go to www.google.com and search again for text items that should give you plenty of ideas.
Let us know what you come up with. Keep in mind that we don't do your work for you, but we're happy to help you with what YOU THINK.
Look at some of these images from the Chicago Convention Riots,
And from Haight-Asbury.
You might contrast the response in these two incidence.