  The primordial Lithium Problem is intimately connected to the assumption that
${}^{7}{\rm Li}$ observed in metal-poor halo stars retains its primordial
abundance, which lies significantly below the predictions of standard big-bang
nucleosynthesis. Two key lines of evidence have argued that these stars have
not significantly depleted their initial ${}^{7}{\rm Li}$: i) the lack of
dispersion in Li abundances measured at low metallicity; and ii) the detection
of the more fragile ${}^{6}{\rm Li}$ isotope in at least two halo stars. The
purported ${}^{6}{\rm Li}$ detections were in good agreement with predictions
from cosmic-ray nucleosynthesis which is responsible for the origin of
${}^{6}{\rm Li}$. This concordance left little room for depletion of
${}^{6}{\rm Li}$ depletion, and implied that the more robust ${}^{7}{\rm Li}$
largely evaded destruction. Recent (re)-observations of halo stars challenge
the evidence against ${}^{7}{\rm Li}$ depletion: i) lithium abundances now show
significant dispersion, and ii) sensitive ${}^{6}{\rm Li}$ searches now reveal
only firm upper limits to the ${}^{6}{\rm Li}/{}^{7}{\rm Li}$ ratio. The tight
new ${}^{6}{\rm Li}$ upper limits generally fall far below the predictions of
cosmic-ray nucleosynthesis, implying that substantial ${}^{6}{\rm Li}$
depletion has occurred--by factors up to 50. We show that in stars with
${}^{6}{\rm Li}$ limits and thus lower bounds on ${}^{6}{\rm Li}$ depletion, an
equal amount of ${}^{7}{\rm Li}$ depletion is more than sufficient to resolve
the primordial ${}^{7}{\rm Li}$ Problem. This picture is consistent with
stellar models in which ${}^{7}{\rm Li}$ is less depleted than ${}^{6}{\rm
Li}$, and strengthen the case that the Lithium Problem has an astrophysical
solution. We conclude by suggesting future observations that could test these
ideas. (abridged)
