  In this brief note insightful remarks are made on the controversy on the
decomposition of the proton spin into the spin and orbital angular momenta of
quarks and gluons. It is argued that the difference in the perception on the
nature of the problem is the main reason for the persistent disputes. There is
no decomposition that simultaneously satisfies the twin principles of manifest
Lorentz covariance and gauge invariance, and partial considerations hide likely
inconsistencies. It is suggested that field equations and matter (i. e.
electron in QED and quarks in QCD) equations must be analyzed afresh rather
than beginning with the expressions of total angular momentum; canonical or
otherwise.
