Wait until one contaminates an urban warren for untold centuries. The media will then blame conservatives - wherever they are for an equal time, if we live that long.
Not likely. A non-nuclear "dirty bomb" is unlikely to be very efficient in dispersing radioactivity. The particulates formed will fall out quickly, and are among the easier things to detect and clean up.
The only real value in such a device is the "scare factor" associated with the word "nuclear".