Being that the annual chance of an American dying in a terrorist attack committed by a refugee is one in 3.6 billion, the reasoning for the ban is analogous to wasting tons of money to make something safer than it already is all in order to save just one more life.
You keep using this statistic. I have to suspect you got it from some sort of "talking point" memo or political diatribe. It doesn't make sense, unless you are fixated on the "refugee" portion, in which case I think you are being intentionally dishonest with regards to this discussion.
There have been AT LEAST 3000 US deaths since (and including) 9/11 caused by terrorists. Just think--the 9/11 terrorists (largely Saudis on visas), Nidal Hassan (Fort Hood shooter), San Bernadino shooter (wife on a visa), Orlando shooter, Boston Bombers...
Over the last (roughly) 15 years, 3000/15 = 200 per year. Since the US population is a little over 300,000,000, that's 200/300,000,000 (roughly) = one in 1,500,000. I don't want to quibble over this rough approximation, but it's clearly QUITE DIFFERENT than the 3.6 billion number you are throwing around.
And I say it's dishonest if you try to parse this and hide behind a "refugee" qualifier, because that's NOT what this thread is about. It's about immigration, refugee or not, that was banned by the Trump Executive Order. In fact, the State of Washington which filed for the stay was found to have standing NOT because of refugees, but because of harm to its visiting faculty to universities, employees, residents, etc. So if you want to talk about the ban in this thread, I'm going to call any sub-qualifier "refugee" status as an attempt to cook the statistics through intellectual dishonesty.