If he is correct and the plague dwindles into nothing he is a genius. If he is wrong and tens of thousands die he is a murderer. Why would he take this risk? Unless, of course, he is absolutely correct and we can stop it. Or he is a demagogic terrorist and the country is devastated.
This is just a theory but do you suppose he may assume that all other nations (at least those through which west africans need to pass) in order to catch a connecting direct flight to the United States may impose the travel ban on them anyways therefore Obama may not need to impose one as the other nations did his dirty work for him?
If Obama imposes a travel ban on west africa it only proves that we were right about the southern border and that's the last thing he wants to do.
Sad but true, Obama is playing politics with ebola