SIM: East vs West fight
So, Weiler has a point - SIM's primary mission is astrometry and planet finding was a secondary mission, originally a side-effect of the high precision astrometric capability. But Marcy is also right, IF there are Earth mass planets within 1 AU of the nearest 3-5 stars, then SIM will see the reflex motion of the star due to those planets orbiting it. A big IF, and one worth doing, although Kepler will be providing data before then about just how optimistic we ought to feel about that.
But, SIM can't wait for the Kepler results. And if it is significantly descoped it won't be sensitive enough to see habitable terrestrial planets anywhere.
What I really worry about is what this is symptomatic of: the natural but insanenly misguided tendency to defend by attacking. GSFC is not well served by attacking west coast centers, Ames and JPL are not responsible for cuts to high energy astrophysics and attacking their mission will only hurt space science overall.
Don't play negative sum games.