What is up with that laugh?

This past weekend Hillary Clinton appeared on Fox News Sunday with Chris Wallace. Wallace began with the following introduction, “Senator, in an interesting bit of karma, we are talking on the first anniversary of my interview with your husband, and I would like to show you a clip from that interview. Here it is.” Wallace played the clip and followed up about a question regarding “hyper-partisan politics.”

Senator, talk about conservative hit jobs, right-wing conspiracies — why do you and the president have such a hyper-partisan view of politics?

What followed was a contrived, shrewish laugh. Was she nervous? What gives?

I say it again. What is up with that laugh?