>"With a heftier backing from the US the Russo-Ukrainian war would be over by now."

And you know this how? Accordingly to all those initial predictions Russia should be already disintegrated and fallen under heavy sanctions, Putin's regime replaced etc. etc. I suspect all these analytics and think tanks should be cleaning toilets instead.

Also there is a line in that backing crossing which may lead to an all out nuclear war. Rational countries that matter understandably do not want to test it unless their existence is really threatened.