Leading global warming advocate/scientist James Hansen recently complained:

Fast forward to December 2009, when I gave a talk at the Progressive Forum in Houston Texas. ... The next day another popular blog concluded that I deserved capital punishment. Web chatter on this topic, including indignation that I was coming to Texas, led to a police escort.

How did we devolve to this state? Any useful lessons?

Hansen has legitimate reason to be upset. Nobody deserves capital punishment for expressing an opinion. Let's turn to Hansen's more general question, however. What"useful lessons" can we draw from this incident? We need look no further than Hansen's own past comments. According to an article in the Guardian from 2008:

James Hansen, one of the world's leading climate scientists, will today call for the chief executives of large fossil fuel companies to be put on trial for high crimes against humanity and nature, accusing them of actively spreading doubt about global warming in the same way that tobacco companies blurred the links between smoking and cancer.

Or, as Brad at WendyMcElroy.com puts it"as ye sow, so shall ye reap." Brad also notes:

Mind you, the"high crime" isn't producing CO2, it is"spreading doubt." Hell of an attitude for a so-called scientist.