It is a war. Ukraine should try and win. If that involves bombing inside the remnant of the Soviet Union, so be it. Who the hell is trying to make up stupid war rules these days?
It’s a war of attrition, just like WWI.
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Ukraine was never going to win. Just survive. NATO and the US should keep funding them. But giving them one weapons platform after another is probably not going to work. Just make sure they don't run out of ordinance. Enough planes so Russia doesn't have air superiority. Slightly better tanks. Artillery doesn't cost that much. This is a fairly old-fashioned war, in spite of the newfangled hacks like drones, and using cellphone signals to home in on troops.
In retrospect, maybe it was inevitable once the WWII generation died off that we idiots would have to relearn the hard way that the way to deal with fascism is to stomp it to death while it’s still a baby snake, before it becomes an anaconda.