  For countably generated ideals, $\Jc$, of $B(\Hil)$, geometric stability is
necessary for the canonical spectral characterization of sums of
$(\Jc,B(\Hil))$--commutators to hold. This answers a question raised by Dykema,
Figiel, Weiss and Wodzicki. There are some ideals, $\Jc$, having
quasi--nilpotent elements that are not sums of $(\Jc,B(\Hil))$--commutators.
Also, every trace on every geometrically stable ideal is a spectral trace.
