In a recent speech, and with no proof whatsoever, Hillary Clinton claimed that GOP-controlled state legislatures with Republican governors are suppressing the vote for millions of mostly young and minority citizens.
If that were true, we would be seeing a decline in overall registration, but as this chart from the Census Bureau shows, U.S. voter registration has been fairly constant with totals actually up slightly in 2012 from the 1996 presidential election when voter I.D's were not required in any state:
The simple fact is that Hillary is desperately worried that blacks won't turnout to vote for her in the same numbers they did for Barack Obama, and it could cost her the election. So, she is now trying to use voting rights as a wedge issue; both in the primaries and the general election in 2016. This whole voter suppression claim is a canard and a false portrayal for political reasons. The same holds true for the youth vote, but Obama himself has poisoned the well on high registration and turnout.
Lastly, while Hillary's tack to the left on Voter I.D. laws might sit well with her supporters for the nomination, it won't do the same for the general electorate. In a Fox poll last year, 70% of those registered voters who were polled, supported I.D.'s. A similar Rasmussen poll, in that same year, found the percentage even higher at 78% and not just for voter I.D.'s but for proof of citizenship to get one.
Hillary: "Republicans Are Systematically And Deliberately Trying To Stop Millions Of American Citizens To Vote": http://www.realclearpolitics.com/video/2015/06/05/hillary_republicans_are_systematically_and_deliberately_trying_to_stop_millions_of_american_citizens_to_vote.html
Voter ID laws in the United States: https://www.google.com/search?q=voter+i.d.&ie=utf-8&oe=utf-8
Census Bureau: Voter Registration and Voting 2012: http://thedataweb.rm.census.gov/TheDataWeb_HotReport2/voting/voting.hrml
Census Bureau: Voter Data 2000: https://www.census.gov/prod/2002pubs/p20-542.pdf
Younger Millennials Have Soured On Obama: http://www.forbes.com/sites/realspin/2014/09/10/younger-millennials-have-soured-on-obama-will-republicans-capitalize/
Why young people don’t vote: http://www.economist.com/blogs/economist-explains/2014/10/economist-explains-24
Poll: 70 percent support voter ID laws: http://thehill.com/blogs/blog-briefing-room/206300-poll-70-percent-support-voter-id-laws
78% Favor Proof of Citizenship Before Being Allowed to Vote: http://www.rasmussenreports.com/public_content/politics/general_politics/march_2014/78_favor_proof_of_citizenship_before_being_allowed_to_vote