President Obama arrives at the Ohio State University spring commencement at the Ohio Stadium on Sunday, May 5, 2013, in Columbus, Ohio. Mr. Obama is the third sitting president to give the commencement address at Ohio State. At left is photographer Annie Leibovitz. (AP Photo/Carolyn Kaster)
President Obama arrives at the Ohio State University spring commencement at the Ohio Stadium on Sunday, May 5, 2013, in Columbus, Ohio. Mr. Obama is the third sitting president to give the commencement address at Ohio State. At left is photographer Annie Leibovitz. (AP Photo/Carolyn Kaster)
President Barack Obama pauses as he speaks at a campaign event at The Ohio State University Oval, Tuesday, Oct. 9, 2012, in Columbus, Ohio. (AP Photo/Carolyn Kaster)
President Barack Obama waves to supporters at Rickenbacker International Airport in Columbus, Ohio, as he arrives for a campaign stop at The Ohio State University Tuesday, Oct. 9, 2012. (AP Photo/Paul Vernon)
President Barack Obama speaks at a campaign event at The Ohio State University Oval, Tuesday, Oct. 9, 2012, in Columbus, Ohio. (AP Photo/Carolyn Kaster)
President Barack Obama pauses as he speaks at a campaign event at The Ohio State University Oval, Tuesday, Oct. 9, 2012, in Columbus, Ohio. (AP Photo/Carolyn Kaster)
FILE - In this Oct. 9, 2012 file photo, President Barack Obama speaks The Ohio State University in Columbus, Ohio. It's more than President Barack Obama's lackluster debate performance that has some Democrats on edge a month from Election Day. Party loyalists, both in Washington and in battleground states, are fretting that Obama's campaign has been slow to rebound after Republican Mitt Romney's commanding debate. They're worried that the Democratic ticket isn't aggressive enough in blocking Romney's post-debate pivot to the political center. (AP Photo/Tony Dejak, File)
**FILE** President Obama arrives Oct. 9, 2012, to speak at The Ohio State University Oval in Columbus, Ohio. (Associated Press)
President Barack Obama speaks during a campaign event at the Ohio State University Oval on Tuesday, Oct. 9, 2012, in Columbus, Ohio. (AP Photo/Tony Dejak)
