The 3rd amendment has never been used in any Supreme Court decisions, and in fact has only ever been used in a single appeals case in 1982[1] (thus there is only one instance of precedence for this amendment -- not to mention that the judge and appeals judge already accepted the Petitioners' argument under the 14th amendment).

I think that a part of the constitution that has only ever been used once, and was based primarily of a fear of a repeat of one of the Intolerable Acts in the 18th Century is hardly a relevant amendment.

[1]: https://en.wikipedia.org/wiki/Engblom_v._Carey