He knows that he's not the one who's going to be pushing the button, but that his rabid out-for-blood base won't even think about that. He's just throwing them meat.
Israel is rumored to have tactical nukes that are much smaller yield than the large ICBMs we hear about all the time. Super destructive force in only 1 or 2 km blast radius, which would even fit inside a small area like Gaza. Of course, in addtition to devastating Gaza, there would still be fallout and issues over Israel, and using them in this manner is definitely Not OK. However, I can believe that there are some deluded people in government (both in Israel and in the US) who would view that as acceptable.
Russia wouldn't get involved. Many of the Jewish Mafia reside in Israel and are essential to maintaining Putin's power in the country. Russia in many ways would be more inclined to encourage Israel to use nukes to cause destabilization in US politics.
These are End Times cultists we are dealing with, the more death and destruction the better so daddy Jesus can come back and punish their enemies. Pathetic sick weak minds.