But the worst manifestations of left-wing extremism occur much further from political power than the extremism of the right.
But force alone cannot solve our problems, and it is no alternative to extremism.
But all they spread in Libya was more tyranny, because Gaddafi did what the United States asked with regard to Sunni extremism.
Passionate "extremism" is part of any political debate, and the more of it the better.
In 2012, Obama will ask Americans if they want a president who abets the extremism of Scott Walker.
Some of them thought he had a few good ideas, but was damaging his own case by extremism.
With all this extremism, we want a man of principle and common sense.
We're also standing against the forces of extremism embodied by the regime in Tehran.
Only the leaders of the New Balkans are much younger, less experienced, more prone to superstition, extremism and moodiness.
We're also standing against the forces of extremism in the Holy Land, where we have new cause for hope.