A few powerful Washington elites?
I believe that would be Sens. Ted Cruz and Mike Lee, and the political extremists are Sarah Palin and the tea partiers. The “incite or create panic” line refers to those tea partiers who tore down the barricades at the WWII memorial and marched to the White House. The extremists waved the confederate flag in front of the White House and chanted things like impeach Obama.
I suspect that Cruz and Palin were not invited, and a Facebook account of their behavior for one vet who was there fits the description of using the event for political gain, “I was disappointed when Ms. Palin and Mr. Cruz walked up to us to say hello but then walked down to the center to try to use us for they’re own purpose so I left to visit the viet nam memorial ty Brats.”