Bruce Schneier explains why:
An empty Washington Monument would serve as a constant reminder to those on Capitol Hill that they are afraid of the terrorists and what they could do. They’re afraid that by speaking honestly about the impossibility of attaining absolute security or the inevitability of terrorism — or that some American ideals are worth maintaining even in the face of adversity — they will be branded as “soft on terror.” And they’re afraid that Americans would vote them out of office if another attack occurred. Perhaps they’re right, but what has happened to leaders who aren’t afraid? What has happened to “the only thing we have to fear is fear itself”?
An empty Washington Monument would symbolize our lawmakers’ inability to take that kind of stand — and their inability to truly lead.