A Duty of a Volunteer Activity

I had a dream.
In it I'm an American student.
The Congress is discussing the insertion a new provision into the Constitution of the United States of America, which requires U.S. citizen to do volunteer activities. I tell my friends that it isn't a volunteer activity, if it is a duty.
My friends and I go to a square to hear a speech given by a Democrat Congressman, who supports this amendment. I hear gunshot and he is shot. I'm quite surprised and turn around. I find a middle-aged man armed with a gun standing still with a smirk on his face. We run away from the square in fear.
In the next day we go to hear a speech given by a Republican Congressman, who opposes this amendment. He is famous for his extreme remarks.
When we arrive at the site where he will give a speech, we lean that his speech is canceled for his safety. I'm disappointed that he ran away in a pinch, although he usually makes extreme remarks.
In the Constitution of Japan(http://goo.gl/9mbbT) there is a provision, which prescribes that Japanese national have a right and duty of working. There might not be such a provision in the Constitution of the United States of America(http://goo.gl/6Y6ND). I think that a constitution basically prescribes authority and duties of a government. I wonder why the Constitution of Japan has such a meddling provision, which prescribes a duty of working.