This remains to be seen.
I'm not convinced it will happen, and won't be until I see it happen.
Certainly great nations can enter in a destructive mass psychology, with new beliefs that would normally never stand up in the light of day. Witness Germany of the 1930s.
But it remains to be seen.
I rather expect this is to be like a bad case of the flu. We will be under the weather, for quite a while. But the antibodies of rationality will prevail in time, saving the body politic from it's darker impulses.
Obama, though, simply because he occupies the bully pulpit, must participate in the impulse towards health. Towards reality.