Yes, pilots should have law enforcement rights in the event of a crisis, just like anyone else should be able to protect themselves in the case of an emergency. Pilots have a great responsibility. If someone is attacking them, they need to be able to fight back, for the good of themselves, and for all of the people on board.
I think that in some situations, a pilot should have law enforcement rights in the even of a crisis. I think that it would be a good way of making sure that a pilot and crew of a commercial airplane can take care of a situation on board just in case there is a hijacking for example.
In the event of a crisis, the pilot should focus on not crashing the plane. If the pilot left the cockpit to go and arrest someone that creates a FAR greater problem than originally existed. IF you wanted someone on the plane to act as law enforcement it would be far more practical to have those duties taken up by someone on the flight crew.
I do not believe pilots should have law enforcement rights in the event of a crisis. Yes, each airplane needs someone with law enforcement rights, but I do not feel it should be the pilot. The pilot has enough responsibility and shouldn't be concerned with anyone else on the plane but himself.