No way Gillibrand should be considered safe, even in New York. She's not well known enough yet and may face a brutal primary challenge from someone downstate. Couple that with the possibility of a prominent Republican other than Peter King getting into the race if things get ugly enough, and I think that seat belongs in the Clear Advantage for Incumbent Party pile instead.
Chuck Schumer (unfortunately) is safe.
Primary challenge comes from the wrong direction to make the seat potentially competitive. Unless, of course, you think Carolyn McCarthy/Maloney would stand a chance in the primary (answer: no).
