Yup. That's the plan. Get back to the moon and THAT would be our launch pad for Martain missions.
But you gotta give NASA the money to do it. You can't just say "Go to Mars" and then "Go to everything else we tell you to do without any more money". So, the current Administration has ordered NASA to go over it's books and see what can be scrapped in order to fund the Ares/Constellation buildups. As it stands now, NASA must pick and choose what gets the appropriate resources and money.
You know what would be a real bitch (and also very hilarious)? If a mission to Mars gets to the Moon and finds a bunch of supplies missing, and a note written in some alien language, as well as binary, that says, "This is an IOU for some parts we had to borrow to fix our hyperdrive. Sorry, but we were behind schedule and had to get home quickly. Thank you, ADFHHFJS, FHUUVNW, and FHJFHUES".