What do the new MECA results show?
The new MECA results are apparently scientifically important enough to suggest notification to the White House. Perhaps they show sulfates or carbonates. Sulfates have already been seen at the MER rover sites so I don't think that would be particularly surprising. Carbonates would be if found in large amounts. Nitrates would be even more noteworthy since the nitrate cycle is such an important part of the life cycle on Earth.
Note that Boynton said this during the most recent news conference and he would certainly be aware of these MECA results so that may have guided his thinking.
Bob Clark