Progressive pundits are chagrined to discover that the Boston Marathon bombers didn't have valid gun permits. It was illegal for them to carry weapons. It was also illegal for them to possess the explosives they used. Oh, and we're not sure yet whether the guns they used were legally or illegally purchased, but given their status, they were likely illegally purchased as well.
Why are they chagrined?
Because this rather pointedly displays the utter futility of the stated purpose of gun control laws. The fact that their weapons and explosives were illegally obtained and used didn't slow down these two terrorists.
Also, there are widespread reports that the weeks events have caused many a Boston-area resident to reconsider their opposition to personally owned weapons. Reality appears to have slapped them upside the head...