"What’s needed is to design experiments that are definitive and avoid years of controversy fomented in part by Levin. My view is that we cannot be certain yet, except that subsurface habitats with liquid water must have existed at some depths and in the more modern record. Levin did not prove that with his Viking gas-exchange measurements of the upper 20 centimeters at the Viking Lander 1 site. But perhaps his attention to these issues has pushed others to pursue better approaches to resolving the issue, such as Phoenix, and other future missions.” - James Garvin, NASA lead scientist for Mars exploration in the space agency’s Office of Space Science in Washington.

Of course, Mr. Garvin here is not being particularly complementary to Mr. Levin. Simply put what he really says is that perhaps some good will come from Levin's nonsensical pursuit of micobes on Mars he didn't actually find.