If you answer the questions on the IRS site addressing "who can I claim as a dependent", the two most controlling answers are whether the child lived with you for at least half the year, and whether he/she contributed more than half of his/her own support for 2016. The IRS further notes that: A person is considered to have lived with you during periods of time when one or both of you are temporarily absent due to special circumstances such as: Illness, Education, Vacation, or Military service. At least in the first "Plebe" year at a service academy, it seems to me that if the kid has spent more than half of his nights in mom and dad's home, and mom and dad paid for all of the support prior to sending him/her off to the academy, mom and dad (assuming filing jointly) should be able to claim the kid as a dependent. I guess the contrary argument could be whether the kid is paying for more than half of his/her support. To me the value of what the kid is receiving in terms of educational and room and board cost from the academy is not dispositive at all. The question, according to the IRS, is whether the claimed dependent is contributing more than half; not whether someone else is. I suppose that an argument could be made that because the child has earned the cost of education, room and board, that it is the child who is paying for the same. In my assessment though, a better (and admittedly more self serving) analysis is that the child is attending a school which does not charge its students for the cost of the education, room and board, and that the child does make a contribution, but the contribution is limited to the amount which is withdrawn from his/her salary, and applied to uniforms, computers....
Although some of you know that I am a lawyer (a judge), I qualify my comments by admitting that I am in no way a tax guy, and am just trying to figure this out like the rest of you. To provide perspective, my mother, who has only a catholic school HS diploma, and is 85 years old, is who I usually call with my general tax questions. I use Turbo Tax because I'm not knowledgeable to do it without the software. LOL. So just sharing thoughts and conclusions here, and take it only for what it is worth.