Social distancing, masks, hand washing and self-quarantine remain crucial. Too little emphasis has been placed on ventilation, which also matters. Ultraviolet lights can be installed in public areas. These things will reduce spread, and President Trump finally wore a mask publicly, which may somewhat depoliticize the issue. But at this point all these things together, even with widespread compliance, can only blunt dangerous trends where they are occurring. The virus is already too widely disseminated for these actions to quickly bend the curve downward.

To reopen schools in the safest way, which may be impossible in some instances, and to get the economy fully back on track, we must get the case counts down to manageable levels — down to the levels of European countries. The Trump administration’s threat to withhold federal funds from schools that don’t reopen won’t accomplish that goal. To do that, only decisive action will work in places experiencing explosive growth — at the very least, limits even on private gatherings and selective shutdowns that must include not just such obvious places as bars but churches, also a well-documented source of large-scale spread.

Depending on local circumstances, that may prove insufficient; a comprehensive April-like shutdown may be required. This could be on a county-by-county basis, but half-measures will do little more than prevent hospitals from being overrun. Half-measures will leave transmission at a level vastly exceeding those of the many countries that have contained the virus. Half-measures will leave too many Americans not living with the virus but dying from it.