Is Putin's alleged meddling in US elections 2016 revenge for US interference in prior Russian elections?
According to this article, Putin thinks [Clinton] interfered in his election - the parliamentary election in December 2011. And so his meddling could be considered payback. Article was linked in this answer.
Of course we cannot know Putin's motives, and lots of info about possible meddling in Russian election would be classified, but is there something in the open which would hint about such meddling?
Of course Putin might consider sanctions for annexation of Crimea, etc as "meddling" and his meddling in 2016 elections would be his asymmetric response.