Throughout gov't offices across the US, there are gov't End-Users using Windows, which has a decades-long reputation for being an unreliable and insecure OS. Macs are cool, but they don't really cater to the needs of the gov't. The only common-sense approach is to replace Windows with Linux.
The US faces cyber attacks from some countries. While "pro-business" Conservatives might disapprove of the stronger system, Linux, in favor of paying a private company, Microsoft, their opinions are irrelevant.
Linux Servers are used throughout gov't, including the White House. But, there are great End-User capabilities, as well. And it's easy now. A whole gov't switch would also stimulate Linux programming.
We'd save Billion$. Don't give in to company bullies. Please finish this before 2017.