History is not on his side. There actually was a previous incident when a drone came down in eastern Iran in December 2011. Either it malfunctioned as the US claimed or, according to Iran, was brought down by their aircraft. US did acknowledge then that the drone was monitoring Iran's military and nuclear facilities. 
It brings to mind the experiences anyone of us might have had at a time when we all went outside for recess and the bully, carrying a stick, his weapon of choice, would advance on our game of hopscotch and try to trip us as we jumped over the squares. When we threatened to punch him out, he ran to the teacher (the UN) to complain that so-and-so had hit him when he "wasn't doing nothing."
This drone incident is just one in a string of provocative behavior going back a long way in our history. A few of the more notorious ones occurred after World War II. In December 1952, the Chinese brought down a plane ferrying four CIA employees into Manchuria. The two pilots were killed in the crash but Richard G. Fecteau and John T. Downey survived. They were on a mission to pick up an agent who was part of a covert operation to establish a "Third Force" to turn back the Chinese revolution. Hearing nothing from the Chinese, the US presumed all four were dead.
Two years later, the Chinese announced that they held two of the men, had tried them, convicted them of espionage, and sentenced them -- Fecteau to twenty years and Downey to life. Downey felt immense relief since he had expected that they would be executed.
The US put out the cover story that they were civilian employees of the United States Army and that their plane had strayed into Chinese territory (I didn't do anything wrong; the other guy is making stuff up). Fecteau and Downey had been told in advance of the mission to use a another cover story. The Chinese had used this discrepancy to force the two to reveal their true status and eventually give information about the agency, which they had, in any case, been advised to do by their unit chief.
The Chinese were willing to negotiate the men's release on one condition: the US would publicly announce that they were CIA spies. Fecteau and Downey waited in prison for TWENTY YEARS until Fecteau's sentence was nearly over (he was released in December 1971) and Downey's had been reduced before a US president was willing to admit the truth. President Richard Nixon in the interests of establishing diplomatic relations with the People's Republic after his 1972 visit there stated at a press conference in January of 1973 that Downey was a CIA agent. 
In 1960, Premier Khrushchev announced that a U-2 had been shot down while flying over Soviet territory -- an international violation of another country's sovereignty (the bully gets in your face). Assuming that the pilot was dead and the plane destroyed, President Eisenhower claimed that the plane was a weather research aircraft that had strayed into Soviet territory (I'm innocent -- I didn't do nothing).
Then Khrushchev in a second statement about the event announced that not only did they have the pilot, Gary Francis Powers (Powers was later freed in a spy swap), but they also had found the plane's camera and discovered pictures of Soviet military installations upon developing the film. Eisenhower had been caught in a very public lie.