Today I listened to one of the best presentations I have ever seen at a scientific conference given by Michael Turner and Edward Kolb. Both are widely respected in the fields of cosmology and particle astrophysics, so the science was great. They also did a wonderful job in their presentations - by that I mean that it was genuinely fun to listen to them talk about the connections between cosmology and particle physics. I left their talks excited about their research, which in my opinion is the mark of successful scientific presentation.
The one thing that did bother me, however, was that several times in their talks they made politically themed jokes insinuating that certain politicians and their supporters were ignorant or backwards. The jokes got some minor chuckles and the talks moved on, but it left me a little unsettled. Upon further reflection, I became even more surprised that such jokes would be made in front of 2,000 scientists, particularly when one of the presenters is clearly sensitive to the politics of science. So the question I would raise for your consideration is "Are political jokes appropriate in an address to a national scientific organization?", or perhaps "what level of political humor is appropriate?"