Based on a comment by mcalex on How does a shutdown end if an agreement is never reached?:
Only non-essential services are shut down atm. None of the answers seem to talk about what happens once current appropriations for essential services run out. Can this happen (say, at the end of the 18/19 FY)? And if so, would it affect given answers?
So, can the appropriations for essential services run out? And what's next if this happens?