Reaching out for help here folks

I've been reading about people bailing out of Bush's administration and many speculate its because of the inevitable oversight hearings and investigations.

Correct me if I'm wrong, but can't Congressional committees subpoena anyone they deem useful to an investigation? And further, if they discover illegal activity, can't the people then be brought up on charges?

In other words, what good does it do to distance oneself from Bush when you're still as vulnerable as ever? Just asking.