Why isn't my car starting? on 2005 Chrysler Pacifica

My 2005 pacifica out of the blue just didn't want to start
I put the key in the ignition and it turns all the way to start but it doesn't come on
The dash lights up and everything but t won't come one
Then when I take the key out it stay on in the on position and uses the battery
I was thinking it was the ignition switch but I was wondering if anybody else or someone who has experience on Chrysler knows what it is.

Asked by for the 2005 Chrysler Pacifica