I believe voting is a privilege given to us by those that fought in the great wars and maintained by the duly elected officials. Given this, it is our responsibility to exercise that privilege when the opportunity arises. I'll bet the Chinese fellow recently awarded the Nobel Prize would vote every chance he got.
The notion of voting as a right is interesting, particularly in the case of people who are incarcerated. A quick search provided this statistic "Although blacks account for only 12 percent of the U.S. population, 44 percent of all prisoners in the United States are black" http://www.hrw.org/backgrounder/usa/incarceration/
It is my understanding that when incarcerated, a person cannot vote. As such, a large percentage of a particular demographic cannot vote therefore cannot possibly influence the political direction that influences their lives while in prison.
As an aside, it was interesting to see the voter turnout in the last US election compared to the last Canadian election. (full disclosure: I am Canadian) For federal elections we barely crack 60% which is shocking. Municipal elections are worse; the last mayoral race for my municipality saw just shy of 30% voter turnout. And that for an election where the elected officials can have a direct impact on your daily life by changing bylaws, tax rates and the like.