The implications of this trial are enormous. In the short term, it could bring the simmering tensions between Holland's approximately one million Muslims and the 1.4 million voters who elected Mr. Wilders to a boil. The Netherlands has seen its share of Islamist violence before and could well see violent confrontations again. On a more fundamental level, this trialeven if Mr. Wilders winscould silence the brave critics of radical Islam. The West is in a war of ideas against political Islam. If free speech is not protected in Europe, we're already losing.