Joe Klien's defenition of left-wing extermist

Joe Klien offers us this helpful cheat-sheet for spotting the left-wing extremists among us:

A left-wing extremist exhibits many, but not necessarily all, of the following attributes:

--believes the United States is a fundamentally negative force in the world.

--believes that American imperialism is the primary cause of Islamic radicalism.

--believes that the decision to go to war in Iraq was not an individual case of monumental stupidity, but a consequence of America’s fundamental imperialistic nature.

--tends to blame America for the failures of others—i.e. the failure of our NATO allies to fulfill their responsibilities in Afghanistan.

--doesn’t believe that capitalism, carefully regulated and progressively taxed, is the best liberal idea in human history.

--believes American society is fundamentally unfair (as opposed to having unfair aspects that need improvement).

--believes that eternal problems like crime and poverty are the primarily the fault of society.

--believes that America isn’t really a democracy.

--believes that corporations are fundamentally evil.

--believes in a corporate conspiracy that controls the world.

--is intolerant of good ideas when they come from conservative sources.

--dismissively mocks people of faith, especially those who are opposed to abortion and gay marriage.

--regularly uses harsh, vulgar, intolerant language to attack moderates or conservatives.

Is left-wing extremism worth worrying about? Discuss.

Update: Ezra Klein weighs in. He says Joe Klien is being "basically irresponsible".