Nothing to stop Russia from using them inside of Ukraine
either naive ...or misleading .....there would be a huge backlash against russia if they did use even tactical nukes if there was nothing stopping them ....russia would have ALREADY done it ! By the counter offensive into Kursk Ukraine have deliberately crossed a putin red line by embarrasing him by attacking and taking russ territory ....putins bluff has been called .
Ukraine cannot afford to not do the same things as russia has - would be like fighting with hand behind your back .
The reason that russia have not so far used nukes is because the cost is .....how the west will respond .....how China would respond ......how the world would respond . US has (privately) told US what their response would be ....we don't know , putin does .....it would certainly need to be a strong deterrent It is certainly NOT in China's best interest for nuclear weapons to be used .....again we don't know ....but I strongly suspect Xi has told putin NO , or we withdraw our tacit support -(which is absolutely vital to russia )
