While the protester's identity and motives weren't clear, from Obama's remarks after he finally gained control of the crowd back, the protester appeared to be an older war veteran.
"This is what I mean about folks not being focused," Obama said. "Hold up. Hold up. First of all, we live in a country that respects free speech. Second of all, it looks like maybe he might have served in our military and we have to respect that. Third of all, he was elderly and we have had to respect our elders. And fourth of all, don't boo, vote!"