  The cross section for the \J~and \U~interaction with light hadrons is
calculated in short-distance QCD, based on the large heavy quark mass and the
resulting large energy gap to open charm or beauty. The low energy form of the
cross section is determined by the gluon structure functions at large $ x$;
hence it remains very small until quite high energies. This behaviour is
experimentally confirmed by charm photoproduction data. It is shown to exclude
\J~absorption in confined hadronic matter of the size or density attainable in
nuclear collisions; in contrast, the harder gluon spectrum in deconfined matter
allows break-up interactions.
