We still don't have their outcome in OH where there were over 126,000. This NPR report suggest they believe many first time voters will forget ID:
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Looking Ahead to the Pennsylvania Primary
Pennsylvania state Rep. Babette Josephs, who chairs the committee that oversees elections, is worried that many first-time voters will forget that they have to show ID.
"And I fear that some of those who have no time to go back home and get ID, that there may not be enough provisional ballots for them to vote, which is a procedure we allow here in the state," she says. Local officials say they're prepared for a heavy turnout, and that there should be enough ballots.
One advantage for Pennsylvania voters is that their provisional votes can be counted, if they're cast anywhere in the correct county. Many states require provisional votes to be cast in the correct precinct — a problem if a voter does not know where that is.
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http://www.npr.org/templates/story/story.php?storyId=89667384&ft=1&f=1001