In summary, RHIC will access 
in the prompt- 
plus
away-side jet channel at 
over the interval
with a sensitivity on 
of about 0.05-0.1.
The interpretation of other channels, like the inclusive prompt-
(no away-side jet tagging), inclusive single jet and di-jet events, is
more delicate.
The 
region covered by RHIC (0.03-0.1) is lower than the
interval covered in COMPASS (0.08-0.35).
In Figure 2.3 the intervals covered in different
measurements are compared.
At RHIC the 
scale is about a few 100's GeV 
and in COMPASS
10 GeV .
The expected accuracy at RHIC for the prompt- plus away-side
jet is similar to the one expected in COMPASS in the open charm process.
In any case a deeper discussion of systematic effects at RHIC is
desirable, before any final conclusion on that can be drawn.
COMPASS can provide significant results on the proton spin structure already
in 2002, while RHIC could most likely come up with first results
not before the year 2003.
Figure 2.3: Comparison of gluon momentum fraction intervals
covered in different measurements.
It is clear that RHIC as a polarized collider will have a far reaching agenda and impact on spin physics for many years to come. However, on the short and medium time scale, COMPASS is likely to provide sooner crucial answers on the specific questions of the proton spin structure.