There were two high-profile murders that were motivated by religious extremism in the past two weeks. The murder of abortion doctor George Tiller in a Kansas church seems to have generated much more media attention than the shooting death of an Army private outside a Little Rock recruiting center.

In a thoughtful essay, Simon Wiesenthal Center Associate Dean Abraham Cooper and historian Harold Brackman ponder "what is the threshold that transforms a politically or religiously motivated violent deed into an act of terrorism?" It's easy in the case of Tim McVeigh, or the white supremacist who went on a shooting spree in Los Angeles in 1999. He tried to breach the Wiesenthal Center, then a Jewish day care center before killing a postal worker.

But there seems to be a hesitancy to label the two shootings acts of terror. It's easy, the authors say, to dismiss these two as crazed loners, but that would not tell the whole story:

"Democratic dissent doesn't spawn terrorism — hatred does. But Muslim leaders should also decry foursquare those religious extremists responsible for helping to brainwash an American young man into a self-declared jihadist whose only reported regret was not being able to gun down more American soldiers.

The bottom line is that Abdulhakim Mujahid Muhammad has no more — but no less — in common with religious Muslims than Scott Roeder has with anti-abortion Christians who would never commit or condone murderous violence in the name of their beliefs. So why the double standard on the part of some important media outlets that seem almost eager to describe Roeder as a Christian fundamentalist and a terrorist — but are loathe to apply similar labels to Muhammad?"

Failure to speak clearly, they say, leaves Americans with "their eyes wide shut" on the threat of terrorism. Read the essay here.