  It was once thought that all coronal loops are in static equilibrium, but
observational and modeling developments over the past decade have shown that
this is clearly not the case. It is now established that warm (~1 MK) loops
observed in the EUV are explainable as bundles of unresolved strands that are
heated impulsively by storms of nanoflares. A raging debate concerning the
multi-thermal versus isothermal nature of the loops can be reconciled in terms
of the duration of the storm. We show that short and long storms produce narrow
and broad thermal distributions, respectively. We also examine the possibility
that warm loops can be explained with thermal nonequilibrium, a process by
which steady heating produces dynamic behavior whenever the heating is highly
concentrated near the loop footpoints. We conclude that this is not a viable
explanation for monolithic loops under the conditions we have considered, but
that it may have application to multi-stranded loops. Serious questions remain,
however.
