  One of the primary goals of the RHIC Spin program is to determine the gluon
polarization distribution within the proton. At leading order, $pp$ collisions
involve a mixture of quark-quark, quark-gluon, and gluon-gluon scattering. In
RHIC, the gluon-gluon and quark-gluon contributions dominate, making the
accelerator an ideal tool to explore gluon polarization. The STAR experiment
has measured the longitudinal double-spin asymmetry $A_{LL}$ for inclusive
production of jets and pions, and for charged pion production opposite a jet,
at $\sqrt{s} = 200 GeV$. The results provide valuable new constraints on the
gluon polarization in the proton when included in a next-to-leading-order
global analysis. The current status of the STAR measurements and the plans for
future measurements will be discussed.
