The first responsibility of the president of the United States is national security. In the absence of presidential leadership as Ebola makes inroads in our country, state officials such as New Jersey governor Chris Christie have stepped into the security breach, taking commonsense steps to protect their citizens from the deadly virus. One of those measures is to quarantine those who have been exposed to Ebola, including health-care professionals who have risked their own lives to fight the disease.

As a public-health precaution, it is entirely reasonable for states to impose a 21-day quarantine that (a) reflects the virus’s incubation period according to scientific research and (b) applies regardless of whether the exposed person is manifesting symptoms. The objections to quarantine, rooted in a skewed construction of the Constitution and the make-it-up-as-you-go-along corpus of international “human rights” law, are frivolous. Yet, they have gotten traction, for at least three reasons.

The first, of course, is the president. What an American president thinks is always a big deal, even if — especially if — it is nonsense. On Ebola as on much else, we deal with our citizen-of-the-world president’s apathy — if not antipathy — when it comes to American national interests. Once again, the responsibilities of his office are subordinated to Obama’s post-American ideological agenda, this time by expending our funds, deploying our troops, and gratuitously endangering our homeland to burnish his legacy as an international humanitarian.

A second reason is Kaci Hickox. She is the nurse and global-altruist-turned-domestic-diva who has very publicly opposed the efforts of New Jersey and, now, Maine to quarantine her after her return from working with Ebola patients in Sierra Leone. On Friday, she found a likeminded judge, Charles C. LaVerdiere, who blithely ordered the quarantine lifted over the objection of the state officials responsible for the security of Maine’s citizens. Third, there is legal commentary, particularly of the libertarian-hedonist stripe, that portrays quarantine confinement as if it were criminal prosecution.

The president, the official singularly responsible for the security of our homeland, should be defending quarantines — explaining why the potentially lethal threat posed by individuals entering our country from Ebola-stricken areas calls for them to shoulder reasonable burdens, like quarantine. This should be unremarkable. Our law, after all, has long made even American citizens subject to warrantless search and detention when attempting to cross our national border. And non-citizens are precluded from entering the United States if they are infectious-disease carriers — just as various flora and fauna that could cause disease are barred. National defense is a basic ingredient and natural right of sovereignty. Our law is thus designed to shield the public from epidemic every bit as much as from military attack.

Yet, in handling the Ebola incursion, Obama has not merely failed to direct a quarantine. As is the case with his non-enforcement of the immigration laws, he has obstructed the states in the exercise of their sovereign power to protect their citizens.

As is his Alinskyite wont, Obama is poisoning the public discussion by ascribing noxious motives to those who favor quarantine. His administration’s straw man of choice is the admonition that doctors and nurses who do the noble work of treating Ebola patients must not be “stigmatized.” But there is no true correlation between quarantine and stigma.

Imposing the inconvenience of isolation on people who have the potential to infect others reflects our humanity toward our fellow citizens. It is why when cold, flu, or other infectious illness takes hold, employees and parents, respectively, are told not to come to work or send sick children to school. When a person fearful that he is becoming ill waves off a handshake, a hug, or a kiss upon greeting a loved one, the natural response is gratitude for the person’s thoughtfulness, not revulsion over the person’s condition.

Plainly, there is no “stigma” attached to the sick or potentially infectious person. Moreover, just as there is nobility in treating the sick, so too is there nobility in protecting others from becoming sick. Going the extra mile to prevent more Ebola infections is, in fact, what people like Ms. Hickox do in West Africa. How strange that she regards extension of the same consideration to her fellow Americans as coercion rather than something she wants to do.

As has been noted over the past few days, the Defense Department has prudently imposed a 21-day quarantine on our heroic troops returning from the hot zones in West Africa. No one thinks of them as stigmatized. Furthermore, among our history’s most revered legends are astronauts who risk their lives to advance science by space travel. They are routinely subjected to quarantine when their journeys end. Indeed, Apollo 11 crew members were quarantined for, yes, 21 days upon returning from the moon. No one thought less of them for it. If anything, the opposite is true. There was the possibility that microbes they’d been exposed to in space could damage their health and, in turn, damage the health of others with whom they came in contact. To promote public health, they were isolated until it could confidently be said, in accordance with the best medical science, that they were beyond the point of falling ill or infecting others.

A quarantine does not diminish our gratitude for the heroic work done by the medical professionals who risk their lives treating Ebola patients, forfeiting the comforts of home for faraway, squalid places. Nor, for that matter, does it lessen our sympathy for the people who have contracted the disease, whether or not they took sensible measures to protect themselves.

So why the suggestion of “stigma”? Because the administration is composed not just of demagogues trying to shame their opposition, but of shrewd lawyers trying to shape the litigation terrain.

“Stigma” is a salient criminal-law concept. There is stigmatization in being accused or convicted of a crime; that is why defendants and convicts get enhanced rights to due process and judicial review. In turn, heightened burdens of proof are imposed on the state. Obama thus wants the courts, to which Ms. Hickox took her case, to look at protective quarantine in the Ebola context as if it were punitive incarceration in the criminal-prosecution context. Ms. Hickox, doing her star-turn in this overwrought drama, carried on as if at-home, non-intrusive, bike-ride-exempted confinement, during which her salary and considerable expenses would be covered by taxpayers, were analogous to being shackled in a supermax prison.