re: Tom M's thoughts: a couple reasons why not.

LRO is not designed *at all* to be a lunar mission. If we wanted to spend a lot of cash on a lunar mission, we should send along gamma ray and neutron instruments similar to the ones on Odyssey finally to clear up the question of polar hydrogen.

Another thing about MRO is that it is specifically designed to act as a high-bandwidth telecom satellite. It is just completely wrong for the moon, because we are so darn close that we don't need that big a dish to talk to earth. If the MER's were operating on the near-side face of Luna (and with a few tweaks) they could send their communications to earth directly. Might even want to look at laser communications.

I'm not against sending orbiters to the moon. It is just that I think that the orbiters should be designed for the task.

And I don't see the moon/mars thing as a zero sum game. You don't need to call for cancellations of exploration of one body to enable exploration of the other.