Thanks for the info hedge. You're right, we're used to seeing the Natl Guard being called out for natural disasters and civil unrest. But even that is pretty rare as the local and state police forces usually handle things.
As far as the link to police fatalities posted by Mortificado, people need to remember that the US is much bigger than the UK and there are local, state, and federal law enforcement agencies. It's estimated that as of 2008 there were over 1.1 million law enforcement personnel in the US. The current number is probably a bit higher as Obama funded more LEOs. For comparison, there are a total of approx 124,000 LEOs in the UK.
The officers who fired fatal shots represent .087% of total personnel based on that 2008 number. And the database linked to doesn't differentiate between justified and unjustified fatalities. Of course, even one unjustified shooting is one too many and officers using excessive or lethal force when it's not justified should face legal repercussions.
I have to admit, it's a touchy subject for me. I know two officers who were shot and killed in the line of duty. Neither had drawn their weapon.