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love the metaphor
The UN can't really do much... the vast majority of resolutions are not legally binding in the first place.
It's basically just a place for people to talk, with zero actual power. >

The UN itself can’t do too much because Russia is on the security council. That said since WWII there has generally been a global consensus on a rules based world order and these values were enshrined in the principles laid out in the UN Charter. A war of conquest in the late 1800s or early 1900s would not have caused much of an international response but a clear violation of the principles of the UN Charter and a threat to the rules based internationally order has triggered a great deal of support for Ukraine. Dozens of countries are sending them weapons and even Russia’s closest allies aren’t joining in in the invasion. Hell Kazakhstan won’t even recognize the illegal annexations and China is refusing to send lethal aid to Russia. 
The UN itself isn’t going to stop Russia but rather countries acting in support of the values of the UN are actively preventing the Russian invasion from succeeding.