(CNN) Washington – The president and his wife were not at home; they were celebrating the first lady’s birthday at a restaurant a few blocks away.
The unidentified object was thrown during a protest, Ogilvie said.
Occupy protesters in Washington rallied at the White House, on Capitol Hill and at the Supreme Court on Tuesday, railing against corporate control at the nation’s most powerful political institutions.
At least one protester was arrested for assault of a police officer, according to U.S. Capitol Police.