This NR article states well why we need a travel ban to help prevent the spread of Ebola in the United States. Excerpt:
The ban should, of course, apply to a traveler’s country of origin, preventing persons from West Africa from entering the United States via other countries. Such a ban would, in theory, have prevented entry to Thomas Eric Duncan, the first person to be diagnosed with Ebola in the United States, who arrived from Liberia via Belgium. Furthermore, it would have protected the two hospital workers who contracted the disease through their interactions with Duncan.
No, the ban would not work perfectly. But an inability to eliminate all risk whatsoever should not disqualify efforts that would reduce it, and restrictions would substantially curtail travel from high-risk nations and minimize the risk of Ebola-infected patients reaching American shores.
The situation in Dallas makes clear that it is easier to protect Americans from the disease by keeping it abroad than by addressing it when it arrives. Screening procedures failed, because prior to boarding in Liberia, Duncan lied about his contact with the disease. When Duncan told staff at Texas Health Presbyterian Hospital that he had just returned from Liberia, they took no notice and sent him home with a fever of 103 degrees. The two hospital workers now suffering Ebola were the victims of minor missteps in following safety guidelines. Even with American health standards and procedures, treating and containing the virus affords ample opportunities for accidental transmission. The U.S. can reduce that risk by instituting travel restrictions that will minimize Americans’ contact with the virus and keep the treatment process, as much as possible, abroad.
No, the ban would not work perfectly. But an inability to eliminate all risk whatsoever should not disqualify efforts that would reduce it.... It's hard to imagine how our leaders can trade this common sense fact for the blather they have been feeding us. But I suspect political correctness and false accusations of racism.