Think about the writing prompt. Which side will you discuss in your argumentative essay?
The United States should pass a law requiring citizens to vote.
The United States should leave the decision of whether to vote to each person?
If we are sharing opinions here, I would go with the choice that the United States should leave the decision of whether to vote to each person. It seems a bit of a stretch and too controlling to force somebody to do something they do not want to do.
