I'd tend to agree
I think the general population would be able to identify more closely with a NASA whose mission is to protect our planet than one whose mission is to put people on Mars. A few years ago I might have said it's just the effect of the mass media...movies like Armageddon and Deep Impact...but who expected to see, in our lifetime, a tsunami kill a quarter million people? It's a terribly grim reminder that uncommon, unlikely events *do* happen.
If the administration's focus were to shift largely toward the exploration of comets and asteroids, we'd still be able to launch some pretty spectacular missions. Be a heck of a thing to put some geologists on an asteroid.