As one who has participated and/or help organize many marches on the National Mall or on Pennsylvania Ave from the Hill to the White House there is an exhilarating feeling anytime in expressing first amendment rights. Sometimes there were times when bystanders joined the march. When that happens you know you are getting the message across to many people. Word is that this march could be one of those cases.
@billybob :
Yup. I marched around the capital in the peace march after W's second inauguration carrying a sign that said "Impeach Bush for War Crimes". I was amazed at the number of people there, especially veterans.