The tilting rotor of a U.S. Marine Corp MV-22 Osprey, being used in support of U.S. President Barack Obama's trip to Chicago, is seen over Chicago April 2, 2014. REUTERS/Larry Downing (UNITED STATES -... more 
The tilting rotor of a U.S. Marine Corp MV-22 Osprey, being used in support of U.S. President Barack Obama's trip to Chicago, is seen over Chicago April 2, 2014. REUTERS/Larry Downing (UNITED STATES - Tags: POLITICS) less 
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Reuters | Photo By LARRY DOWNING / Reuters
Wed, Apr 2, 2014 6:31 PM EDT