  We discuss the shortfalls of existing resolutions of the long-standing gauge
invariance problem of the canonical decomposition of the nucleon spin to the
spin and angular momentum of quarks and gluons. We provide two logically
flawless expressions of nucleon spin which have different physical meanings,
using the gauge independent Abelian decomposition. The first one is based on
the assumption that all gluons (binding and valence gluons) contribute to the
nucleon spin, but the second one is based on the assumption that only the
binding gluons (and the quarks) contribute to it. We propose the second
expression to be the physically correct one.
