University of Chicago professor John Mearsheimer

University of Chicago professor John Mearsheimer explains why Russia does not want Ukraine to join NATO

"Ukraine, which is now a de facto member of NATO <...> just invaded Russian territory. That is precisely why the Russians do not want the Alliance, which was a mortal enemy during the Cold War, and, it seems, after it, to expand into Ukraine or Georgia," he says.

That is why Moscow has made it clear that it will not allow anything like that, the professor added.