So much has been written about the Department of Homeland Security memo about right-wing extremism that I finally broke down and read it. Well, that isn't completely accurate: I skimmed it. I also read the companion piece on left-wing extremism. (Thanks to Jeff for providing links to both.)
The memo on left-wing extremism talks about the danger that environmentalists, animal activists or anarchists may hack into and destroy computer systems of companies whose actions they oppose. It lists a number of recent incidents and describes how the reliance of various companies on their IT systems continues to grow in order to make its point. All in all, it struck me as a reasonable piece of analysis. It left open the question of the relative threat posed by other activities of these groups, such as arson, but at least it made sense internally.
The memo on right-wing extremism consists of speculation; what facts it marshalls date from the 1990s. Analytical pieces based on 20-year-old, spotty data usually don't see the light of day. (Was Timothy McVeigh part of a trend? No evidence of that.) It came to light just as Obama top advisor Axelrod was characterizing the tea parties as 'unhealthy' - a context that certainly puts it in a highly unfavorable light.
The White House has distanced itself from the report. If President Obama is smart, he'll disown it.