H. says, "Students have new ammunition in the fight to lean back in their chairs!"
To which D. replies, "Sorry, just because so-and-so (even if it the President Of The United States) does it, it doesn't make it right."
D.'s argument is not without merit, but I believe it is essential that children be allowed to emulate the President and lean back in their chairs. Falling on one's head, or getting the wind knocked out of them when the chair passes its tipping point, provides an early and practical lesson in physics, balance, consequences, and the rationale for listening to authority (which is why it is also essential to tell children NOT to do this, even while recognizing the value inherent in the behavior). Elementary school children (and possibly U.S. Presidents) are 67.4% less likely to sustain a serious physical injury as a result of "backfall." Children, because they are naturally resilient; U.S. Presidents because their Secret Service detail has been trained to dive across the room in under .45 nanoseconds so as to cushion the President's fall.
It should be noted that several important diplomatic protocols would be breached should anyone but Mrs. Obama attempt to point out to the President the likely consequences of leaning back and tipping his chair. Even Mrs. Obama would be permitted only the most subtle of raised eyebrows unless First Daughters Sasha and Malia were also present in the room, allowing the First Mother to use the First Father as an example to them of "what not to do even if you're the leader of the free world."