An exhibit of psyops leaflets released in Iraq, Afghanistan and Libya finally shows American people the messages that were made in their name By Moustafa Bayoumi For over a century, the United States military has been dropping propaganda leaflets in deliberate psychological operations, or psyops, to achieve success in war. But the key question behind the effort remains unanswered: does it even work? In 1918, the US released more than 3m leaflets behind enemy lines by plane and hydrogen balloon.