While speaking on the bull horn, the mic switches from President Kirkman's left and right hand when looking from the front or back.
An explosion large enough to destroy the Capital would entail a crime scene of nearly half a mile in every direction. It is inconceivable that spectators would be allowed that close to the scene or for that matter the President.
Jason asks Hannah to prove her theory. However, a theory cannot be proven, it can only be falsified.