The Ebola virus, which has already killed more than 1,500 people since the epidemic began earlier this year, is wreaking havoc in West Africa, leaving death, economic hardship, social stigma and civil unrest in its wake.

In response, the Obama administration has stressed that the disease is highly unlikely to spread inside America. Given international travel, we will certainly see cases diagnosed here, and perhaps even experience some isolated clusters of disease. For now, though, the administration's assurances are generally...