The point is this woman was not armed, did not have a bomb and never even drove through barrycades. She had no chance of getting anywhere near Obama. She was probably terrified by a bunch of roided up cops screaming and pointing guns at her so she tried to flee.
If you are buying into this myth that its OK to shoot anybody getting near government buildings you need to re-think.
Look, I'm getting tired of this strawman.
This woman didn't "get near government buildings" because she was stopped by barricades designed to prevent it. But, if that was all she had done, it would have ended peacefully.
When she was thwarted at the White House, she drove off at high speed after striking a Secret Service officer. In my state, that is considered aggravated assault. If he had died, it would have been at least manslaughter.
She was nearly cornered at the US Capitol, but managed to escape:
You can even watch the video: http://www.youtube.com/watch?v=CyszhTz8fQ4
This woman was given multiple opportunities to stop. In retrospect, it's easy to say she was just scared. But, at that moment she was almost indistinguishable from a genuine threat.
If she had struck and killed an innocent tourist, most people would be wanting to know why the cops didn't stop her when they had the opportunity.