That's because she's been keeping her mouth shut -- every time she opens it, the crap spills out!
I'd agree that part of Hillary's strategy has been to keep a relatively low profile.
But to the extent she has spoken out, it has been in a very calculated attempt to reposition herself as a pro-defense moderate, as in her statement on abortion and her remarks in Iraq last week to the effect that the elections were a rebuke to the insurgents.
This is her first bad misstep I can recall in recent times.