You are one of the few to notice this.

Actually, all elected politicians have auras. Something about the job gives them this glow. You can pick them out of a crowd, even if you don't know the politician or personally seen them before.

About two years ago, my local MLA (a backbencher in the Alberta legislature) entered the same restaurant my mother and I were dining. While she did look like her picture (I had never seen her personally), there are probably 100 other women in my town who could look like her. But she shined. So I knew right way she was the MLA.

There was lots shining at the DNC. So much that you probably only noticed the senators.

Political rallies are indeed stimulating. Lots of shining.