Let’s forget about the GOP “hypotheticals” that Hamas militants will deliberately infect themselves with Ebola and sneak into the U.S. from Mexico to wreak havoc. Or that gay soldiers getting “massages all day” will make them less able to perform adequately in West Africa and against terrorists. Or even the suggestion that if Mitt Romney were president we wouldn’t have an Ebola problem.

The more serious issue is what to do about the disease now that it is here, and the seemingly willful ignorance coming out of the administration borders on caricature. On Friday October 17th, White House spokesman Josh Earnest observed that “Putting in place a travel ban could have a pretty perverse effect on people who are seeking to travel to this country.”

The debate over what to do about Ebola has demonstrated that even high government officials don’t have a clue regarding how the U.S. immigration system actually works and what can be done reasonably to reduce the likelihood of infected travelers entering our country. President Obama has argued that “We can’t just cut ourselves off from West Africa,” while refusing to ban travelers from the region. Obama doesn’t quite get it, as no one reputable is demanding “cutting off” from West Africa, though many serious observers would like to see the travel of possibly infected visitors suspended until the health crisis passes. Health-care workers and aid agencies would still be able to enter the countries in question on available flights and using chartered and military aircraft.

So in truth, carefully managing travel of visitors from an area where there is an epidemic is not the same as trying to “seal off an entire region of the world” as the president chooses to describe it. Having worked the visa line in various overseas diplomatic assignments, I think I have a good understanding of what can be done very simply to modify an immigration policy in response to an epidemic overseas.

While the State Department issues the actual visas for travel, it is the U.S. Customs and Border Protection Service (CBP), part of the Department of Homeland Security, that handles the actual entry of returning American citizens, temporary visitors, and foreigners who expect to reside in the United States. A foreign traveler arriving at a U.S. airport seeking to enter the United States is first confronted by a CBP official who confirms that the visitor has the proper documentation to enter the country. There is then a stop at customs, also part of Homeland Security, before actually entering the United States. Any American citizen who has traveled outside the U.S. and then returns is also familiar with the procedure.

The three neighboring countries in Africa that have become the epicenter of the Ebola contagion are Sierra Leone, Guinea, and Liberia. Any citizen of those countries traveling on that country’s passport needs a U.S. visa to enter the United States. Currently 150 travelers from those countries are arriving daily in the United States, which means nearly 5,000 visitors a month. There are also a reported 13,000 visas that have been issued and not yet used. Liberian citizen Thomas Duncan, who died in Dallas, arrived on a visitor’s visa.

Visas are approved and issued by Foreign Service Officers serving in the Consular Sections of U.S. Embassies and Consulates. There is a whole alphabet soup of different kinds of visas, including “Diversity” visas handed out by lottery, but the most common type, the B-2, is issued for temporary tourist travel to the U.S. under the assumption that the visitor will be returning home, normally within 90 days. U.S. immigration law requires that that determination be made and the State Department guideline notes that “Visa applicants must qualify on the basis of the applicant’s residence and ties abroad, rather than assurances from U.S. family and friends.” While State Department officers frequently make judgment calls and some are regarded as particularly sympathetic and therefore highly sought after by the local visa seekers, few would jeopardize their own careers by giving a visa to someone whose desire to return home is problematical.

As the American visa officer is supposed to establish to his or her own satisfaction that the traveler has connections with his or her own country, usually consisting of a job, property, or family that would mandate his or her return, the processing of Duncan, a driver for a cargo company with a girlfriend, sister, and son in the U.S., should have raised some concerns about his intentions. Duncan in fact quit his job shortly before departing for the U.S., but that is something the Embassy visa section would not have known. As the State Department is not revealing how the decision to let Duncan enter was made, one has to assume that he somehow demonstrated his viability as a temporary visitor who intended to return to Liberia before his visa expired.

The case of Duncan aside, the local embassy has considerable discretion in issuing a visa. But even though limiting travel from an area where there is an epidemic of an often fatal illness could certainly be construed as grounds for denying a visa, such a blanket decision would have to come from Washington. And it would have to overcome an in-built bias in a system intended to serve U.S. interests abroad, but which frequently leans over backwards to cater to the local constituency. For example, the Freetown Embassy somewhat oddly refers to Sierra Leoneans as its “clientele.”

As the White House is opposed to any travel restrictions, the embassies in question are continuing to approve and issue visitor visas as if nothing is happening, though the Monrovia, Liberia Embassy website indicates that there is an Ebola symptoms screening carried out by local contract guards before applicants are allowed to meet an American officer. There are no special security arrangements in place in Freetown, Sierra Leone and Conakry, Guinea.

Because the unavailability of visas would constrain most travelers, the arguments being made by some in the government and media that a travel ban would require halting flights that go to the three countries and would thus amount to an externally imposed blockade are essentially false. If the intention is to reduce the flow of possibly infected visitors from entering the United States, all that is necessary for most travelers is to stop issuing visas and to suspend the visas that have already been issued but not yet used. That would block most of the potentially infected.

As the propagation of any communicable disease is inevitably a numbers game, the fewer infected travelers that actually enter to the U.S. mean fewer Americans will get infected in turn. And the apparently only semi-prepared U.S. medical system will avoid being overwhelmed by the situation. No one is denying that Ebola will find some way to our shores in any event, but reducing the numbers coming in is critical to isolating and containing the virus. Stopping the issuance of new visas and suspending those already issued would have a dramatic impact.

Some have argued that many West Africans have second passports issued in Western Europe or even the United States and they would be able to travel without visas, connecting through airports in Europe or North Africa. This is because most European countries are in the visa waiver program which means their citizens can travel to the U.S. freely while their governments offer reciprocity to American travelers. This is true enough, but flight manifests, which can be requested by the Department of Homeland Security from the relevant carriers, would reveal where the travel originated and measures already in place for the health screening of those relatively few individuals can either be continued or strengthened. In this case the problem is relatively simple as only two carriers operate between all three of the affected countries and other airports that in turn connect to the U.S. They are Brussels Airlines and Royal Air Maroc. Air France has flights to Conakry.

The point being made here is that there should be some control over who enters the United States when crisis situations develop overseas without the issue becoming a political football. Restricting visas in this case means lessening the number of potentially infected travelers coming from a region where there is a virus epidemic that kills 70 percent of those who acquire it. Such action will inevitably lessen the number of people on this end who might come down with the disease.

That such a simple step is either not appreciated, possibly not understood, or perhaps is being resisted for political reasons by the federal government could have tragic consequences.

Philip Giraldi, a former CIA officer, is executive director of the Council for the National Interest.