That's the recommendation of a new Pentagon commission.
http://www.cnn.com/2009/US/07/12/military.smoking.ban/index.html
Argument is that tobacco use can impact military readiness. I can testify to that. When I was in, most those who could not pass the run on the PT test were smokers. When they told me they were doing everything they possibly do to pass the test, I'd point out to them that so long as they were still smoking that was not true.
"A man never drinks anything that a plant lives in" --DBone (A Real Man).
http://vimeo.com/4938173