And is partly responsible for the fact that they have made themselves so perilously close to institutional extinction. A "search for ET life" is a mission, all right. the only problem is, it's a mission with a low probability for success.
The book Rare Earth actually claims that bacterial ET life is probably quite common -- Ward and Brownlee claim that advanced, intelligent life is rare (let alone technologically advanced life), mostly because the planetological factors responsible for the creation and evolution of the Earth appear to be unlikely (not impossible) to be reproduced elsewhere.
NASA's mission should be to explore the universe with people and machines. Period. Leave the "search for life" stuff to the Saganite Planetary Society and other California flake groups.
Flake groups? ROFL! I know I am in good company. :)