Although much can be learned about the pomeron at HERA, there
are distinct advantages to studying hard diffraction at the Tevatron.
Diffractive systems with mass greater
than 450 GeV/
can be produced
at the Tevatron compared to only 70 GeV/ at HERA. This allows for
the production of high 
objects at the Tevatron (such as W or Z bosons)
as well as large jet cross sections.
Without these large cross sections it is impossible to study high |t|
exchange since the cross section decreases so steeply with |t|
(Fig. 5).
The super-hard pomeron can best be studied at the Tevatron,
since at HERA it can result only from
a higher twist diagram, which is suppressed
(gluons from the pomeron cannot connect
directly to the photon, but must connect to the hard scattering, a
configuration which is suppressed) [32].
Double pomeron exchange obviously cannot be studied at an ep collider.
Finally, one of the key results will stem from the comparison of
pomeron structure in ep and
collisions. If the pomeron behaves
like a particle it should have consistent structure independent of the
nature of the probe (electron or proton).