Nationwide Medicaid expansion should be part of our emergency response to coronavirus.

Texas, Florida, and 12 other states are putting lives at risk across America by refusing to extend Medicaid coverage to millions who are poor and uninsured. This ensures that many Americans who become infected will go undiagnosed and untreated: people for whom going to the doctor portends financial calamity tend not to do so before their health circumstances become dire.

Consider these numbers: upwards of two million uninsured Americans would gain coverage were these 14 states to immediately expand Medicaid under the Affordable Care Act. The price-tag for these states would be a bargain since the ACA obliges the federal government to pick up 90 percent of the tab for making Medicaid available to people with incomes up to 138 percent of the federal poverty line.

Now consider the threat. It’s been projected that the virus will infect from 40 to 70 percent of the world’s population this year. If this estimate is ballpark-accurate for our country’s poor and near-poor, many of whom live in close quarters and lack access to resources needed to reduce transmission, then  — do the math — expect 800,000 or more of the two million-plus Americans being denied Medicaid to contract coronavirus.

And keep in mind their well-founded fear that without insurance, any encounter with the health care system could result in financial disaster. The sure result will be a reservoir of hundreds of thousands or more infected people beyond the reach of medicine.

The nightmarish consequences of this would include (in addition to avoidable suffering and death for the financially worst-off among us) national inability to track sources and surges of coronavirus infection, as well as the inability to target quarantine, rapid clinical response, and other public-health powers so as to dampen these surges.

The affluent among us would hardly be immune to the additional deaths, suffering, and economic disruption that this reservoir of untracked, untreated disease would visit upon our country.

Early evidence suggests the new coronavirus is more contagious than seasonal flu. It spreads through the air, human touch, and contact with inanimate objects, and it survives on surfaces for unknown amounts of time.

Wealthy people’s fantasies of eluding it by living apart in luxe bunkers and tropical retreats linked by private jets will be foiled by the mundane realities of food and service provision (their canned tuna won’t last forever; neither will their bunkers’ plumbing). Contagion is humanity’s great economic leveler.

Conservatives who reject Medicaid expansion (and public funding for health care more generally) cast it as welfare and dismiss the poor as undeserving. Many hold to a classic vision of minimal government, limited to protecting liberty and property and providing for the common defense. Public provision of safety-net services to the least advantaged among us has no place in this crimped view of our duties to each other, no matter its potential to ameliorate suffering.

At least since President Franklin Roosevelt pushed unsuccessfully for national health insurance in the 1930s, right-wing opponents of health care for all have treated it as excess, beyond the proper scope of minimal government.

This belief comported with the common impression that life-threatening mass contagion was a thing of the past, at least in advanced nations. The public sanitation revolution of the turn of the last century, followed by the advent of antibiotics and the proliferation of vaccines, had taken infection off the table as an existential threat, or so it seemed.

Perceptions of health care as a species of welfare, beyond minimalist government’s realm of responsibility, persisted through the growth of antibiotic resistance and the emergence of viral menaces such as AIDS, Ebola, and SARS. But the terror that paralyzes economies crashes stock markets, and has millions feeling like extras in a disaster movie-turned-real should shock even the most hard-core conservatives into recategorizing medical care as critical to our common defense.

“This is not a drill,” WHO Director-General Tedros Adhanom Ghebreyesus warned last week. Americans — even those with fear and loathing for the welfare state — need to get behind the full mobilization of the fighting force we need.

Immediate Medicaid expansion in the states that have said “no” will begin to stand up that force within weeks among people for whom coronavirus would otherwise go untracked and untreated.

This should be just the first step toward a bipartisan embrace of health care for all, as a matter of national security. The proposition that we can deny care to some without putting the rest of us at deadly risk has been given the lie.

M. Gregg Bloche, M.D., J.D., s a professor of law at Georgetown University and co-director of the Georgetown-Johns Hopkins joint degree program in law and public health. Follow him on Twitter: @greggbloche.