Why All The Death Threats?

At what point did it become acceptable to send death threats to your political opposition? We've seen a significant increase in that kind of behavior from the left in the past few weeks. Threats have been targeted at Republican legislators and the Governor in Wisconsin, Wisconsin blogger Ann Althouse, filmmaker and sting artist James O'Keefe, and many others. Glenn Reynolds thinks he knows what's going on:

My theory is that they’re all about displaced anger at Obama. He’s been a failure, but they can’t bring themselves to hate him, yet. So they turn the hatred elsewhere.

I think he's on to something. The frustration the left feels at electing Mr. Rainbows and Unicorns and then finding out he was an impotent leader despite his big legislative majorities must be psychologically crushing.  Obama didn't pay their house and car payments like they thought he would, he didn't free the gays like they thought he would, he didn't punish the rich like they thought he would, he didn't get us out of Iraq and Afghanistan like they thought he would, he didn't close Gitmo like they thought he would, he didn't bring peace and harmony to the world and make everybody love us like they thought he would...ad nausem.  And his one signature accomplishment, Obamacare, yielded one of the biggest electoral bloodbaths in history.

They're angry, but they don't dare direct their anger at the actual cause because they're afraid someone will call them racist.