Assuming a 4% case fatality rate (from hospitals being overwhelmed), that would mean ~40.8M cases.
At recent rates of growth we'd reach that in 27 days.
#ShutItDown
If 20% of Americans get the virus (same as Diamond Princess), and 1% of true infected die, this means 65.4M true cases and 654k deaths. If we eventually confirm half of true cases, that's 32.7M confirmed cases, which we'll reach in...26 days at current rates.
So we don't have a lot of time. Shut everything down now.