"Although most people opposed violence, a significant minority (ranging from 5-14 percent) agreed with each violent option, and 10-18 percent expressed indifference about violence in politics. This implies that millions of ordinary Americans endorse the general idea of violence in politics.

"Interestingly, these violent attitudes did not depend on standard political and demographic characteristics. For example, Republicans and Democrats were indistinguishable in their support for political violence, and liberals and conservatives were too.

"By far the strongest factor is an aggressive personality. People who behave more aggressively in everyday life are significantly more likely to support political violence."

Text of research paper here:
http://papers.ssrn.com/sol3/papers.cf...
"The results from Table 8 suggest that Democrats might be more responsive to violent
rhetoric."
"The results in Table 10 show substantively- and statistically-strong treatment effects
among low-knowledge subjects, consistent with the patterns observed above. In contrast, high knowledge subjects show virtually no responsiveness to the violent rhetoric."