How many times in the New Testament does Christ refer to "Natural Law?" Frankly, Paul tells us many times that Christ came to supplant "Natural Law" in favor of "Spiritual Law."
As for "staying out of conflicts which aren't your business," this is the most counter-Christian thing I've ever heard. If Christ "stayed out of conflicts that weren't His business" He'd have never stepped in to stop an adulteress from being stoned. If Elijah stayed out of conflicts that weren't his business he'd have never given a widow a command to collect vessels and sell the oils from them to save her children from being sold as slaves. If David had stayed out of conflicts that weren't his business he'd have walked away saying "man, I hope somebody does something about that Goliath guy." The very notion that there exists a conflict that isn't our business goes against Christ's commandment that all on Earth are to be regarded as neighbors and brothers. The argument you have presented is an attempt to mask cold and cynical apathy to the suffering of others as some form of "Christian virtue," which it most assuredly is not.
Not only that, but the aggressor in question has openly and repeatedly declared that we are his next target. Learn some Russian and watch their TV channels. Putin's own State Duma declares this on an almost daily basis. Even in the absence of any concern for one's brethren (an absence which seems to be the sad state of many Americans who profess, albeit unconvincingly, to be "Christians"), basic self-preservation teaches "shoot the bear before it eats this guy and I won't have to face it when it comes looking for me after getting bigger from its meal."
To those who laughably pretend to be American "patriots" while making excuses for inaction in Ukraine, while masking their desire to give up and let Russia keep what they have gained - including the subsequent enslavement of more than 14 million people who are regarded as second-class under Russian Law for the "crime" of being born Ukrainian (and don't try to pretend this isn't the case because there are 86 terabytes of documented proof that it is so) - as "peace," I say this. If the French in the 1770's had the mindset you have, the country you call yourself a "patriot" of, wouldn't exist. The rag-tag Colonial militia didn't beat the British Empire without being constantly armed and aided by more powerful nations abroad. If the French in the 1770's had said "we shouldn't escalate by arming that loud-mouthed Washington fellow who keeps begging for weapons; we should stop arming him so the conflict will end," there'd be no America. If the French in the 1770's had said "this is between Britain and the colonists, it's not our business," not one individual on this forum would exist. When you say "pray for peace," what you mean is "pray the victims quietly accept subjugation so I won't have to be bothered with their plea for aid." "Peace" has never once in Human history been achieved by making concessions to a predator. There has not been one documented instance in the entire chronicles of Human history when peace has been achieved through any means other than the destruction, by force, of an aggressor.
Anyone whose attitude to this conflict is anything other than condemnation of the invader and a firm resolve to support the resistor as long as is needed, and to fast and pray daily for their swift and total victory... is neither a Christian nor an American patriot, and there are no two sides of that story. Any who wish to reply may do so, but I've said my final word on this subject and I'll go a step further by saying I'm the only one on this site who speaks on this subject from BOTH first-hand experience AND more than a decade of research.
May God open the eyes of those who choose to stay blind and call their blindness "piety" and their apathy "patriotism."