School Obama's Daughters Attend Has 11 Armed Guards
The school, Sidwell Friends School in Washington, DC, has 11 security officers and is seeking to hire a new police officer as we speak.
If you dismiss this by saying, "Of course they have armed guards -- they get Secret Service protection," then you've missed the larger point.
The larger point is that this is standard operating procedure for the school, period. And this is the reason people like NBC's David Gregory send their kids to Sidwell, they know their kids will be protected from the carnage that befell kids at a school where armed guards weren't used (and weren't even allowed).