@vimothy, surely as a realist, you can see that this is true? The US-UK invasion of Iraq was illegal, and the legal consequences have been nil. Russia's invasion of Ukraine is illegal, and the consequences have been nil. Israel routinely acts illegally, as it's doing right now, and the consequences are always nil.
The only time international law is actually applied is when a powerful country, or an organisation of powerful countries, enforces it on a much weaker country. This isn't always a bad thing - I don't shed any tears over NATO stopping Milosevic's tinpot Nazis in their tracks, for example - but that hardly strengthens the case for international law being effective, because strong countries enforcing their will over weaker countries has happened since forever, long before any such idea as 'international law' existed, and usually for much less noble causes than preventing genocide.