The recent story of a Liberian man in Dallas who had Ebola sparked a political conflagration around travel restrictions for countries where there are Ebola cases. The virus does not appear to have spread from him to anyone that did not come into direct contact with him in the Dallas hospital.

Many are arguing that his arrival in the United States means that all travel from the affected West African countries should be shut immediately. Others are arguing that travel should remain as open as it currently is – which is still heavily restricted.

What happened to policy responses on the margin?

Fortunately, the federal government took a marginal action yesterday. Fliers from Guinea, Liberia, and Sierra Leone will have to enter through one of five ports of entry and undergo an interview as well as a temperature check once they arrive in the United States. These restrictions are far less than the total ban sought by some folks and still more restricted than the current system These checks do not interrupt the flow of aid to these West African countries either and will affect roughly 150 travelers per day.

Immigration or movement restrictions for legitimate health concerns are proper and already written into law. Travel restrictions to contain viruses different than Ebola have not been successful in the past. Ebola is far less communicable than the flu so the comparison to previous travel bans might not be appropriate.

Americans have a very low chance of contracting Ebola while in the United States, let alone dying from it. The only person to die from Ebola in the United States contracted it in Liberia. I took a bigger risk of dying from a traffic accident this morning commuting to the office than I will ever face from Ebola.

More Americans are killed every year from their furniture than all Americans who have died from that dreaded hemorrhagic fever.

Those Americans who worry about Ebola focus on the freakishly high death rates for those who contract the virus – 50 percent for most strains of the virus (only 20 percent of Americans who have contracted Ebola have died.) But the death rate is not the most important figure; the chance of contracting the virus in the first place is the most important factor.

So far, two American nurses who treated the Liberian man contracted Ebola from him. Both nurses are recovering. For the rest of us, that means the chances of contracting Ebola is about zero. No matter the death rate, a zero chance of contracting the disease means we will not die from it.

Still, a few marginal precautions, like those put in place by the federal government, will impose a very small temporary cost and likely stop any future Ebola patients from coming to the United States on a commercial flight.