Opinion Rabbis stand near an installation commemorating the victims of Babi Yar, one of the biggest single massacres of Jews during the Nazi Holocaust, in Kyiv, Ukraine, Sept. 29, 2020. Photo: Reuters / Gleb Garanich. As the crisis targeting Ukraine unfolds, some countries are quietly planning for the prospect of millions of refugees should Moscow launch a full-blown invasion. While not all surrounding nations would necessarily welcome large numbers seeking safety, for one potential group — Ukrainian Jews — there are much clearer, and more reassuring, possibilities, should they feel compelled to leave. The reason is simple: Israel exists. It...