When President Barack Obama travels abroad, his staff packs briefing books, gifts for foreign leaders and something more closely associated with camping than diplomacy: a tent. Even when Obama travels to allied nations, aides quickly set up the security tent which has opaque sides and noise-making devices inside in a room near his hotel suite. When the president needs to read a classified document or have a sensitive conversation, he ducks into the tent to shield himself from secret video cameras and listening devices. American security officials demand that their bosses not just the president, but members of Congress, diplomats,...