  Two groundbreaking new facilities will commence operations early in the 2020s
and thereafter define much of the broad landscape of US optical-infrared
astronomy in the remaining decade. The Large Synoptic Survey Telescope (LSST),
perched atop Cerro Pachon in the Chilean Andes, will revolutionize the young
field of Time Domain Astronomy through its wide-field, multi-band optical
imaging survey. At the same time, the James Webb Space Telescope (JWST),
orbiting at the Sun-Earth L2 Lagrange point, will provide stunningly
high-resolution views of selected targets from the red end of the optical
spectrum to the mid-infrared. However, the spatial resolution of the LSST
observations will be limited by atmospheric seeing, while JWST will be limited
in its time-domain capabilities. This paper highlights the scientific
opportunities lying between these two landmark missions, i.e., science enabled
by systems capable of astronomical observations with both high cadence in the
time domain and high resolution in the spatial domain. The opportunities range
from constraining the late phases of stellar evolution in nearby resolved
populations to constraining dark matter distributions and cosmology using
lensed transient sources. We describe a system that can deliver the required
capabilities.
