John Moore/Getty Images Perhaps the greatest success of the American health care system these last few benighted years is this surprising fact: The uninsured rate has reached a historic low of about 8 percent. That’s thanks in part to the pandemic — or, more precisely, the slew of emergency provisions that the government enacted in response to the Covid crisis. One policy was likely the single largest factor. Over the past three years, under an emergency pandemic measure, states have stopped...