The war was fought to preserve the Union. It didn’t become about slavery until much later (on the Union side, at least. The South fought for slavery from the very beginning).
And to make it three for three, I’m not sure the US cutting off trade to anyone counts as military intervention regardless of the later military actions of the country being cut.
Yeah, Lincoln basically retconned it into a fight to end slavery when it became apparent that support for the war was waning. Lincoln personally didn’t care if slavery ever got ended; his letters make this clear.
Fascist Italy justified their invasion of Ethiopia in part on the grounds of abolishing slavery. Which should make us all very suspicious of ‘humanitarian’ arguments for international occupations. Though I will certainly give the Vietnamese Communists lots of props for taking out Pol Pot.
“Slavery” was at the root cause of any issue that caused the Union to need preserving. You can play the “state’s rights” or “preserving Southern culture” cards if you like, but it was about state’s rights and culture of owning black people.
The Civil War certainly wasn’t fought for humanitarian reasons on the Union side; it was fought by the Federal government as a matter of national survival for the United States. And Lincoln made it clear in the early part of the war that he did not believe he had any authority as President of the United States to abolish slavery, and that as President of the United States he believed it was his paramount duty to preserve the Union; that is, to prevent the country he had been elected to be president of from being destroyed.
But it’s a massive overstatement to say that Lincoln “personally didn’t care if slavery ever got ended”; he was clearly personally and politically opposed to slavery, and had been for many years before he was elected President.
Both sides of the Civil War knew that if the north won, slavery would end. So while yes, their were other issues I’d still say ending slavery was a central part of the war.
Dude, it really was not a humanitarian war 
No, the South went to war against the North to preserve slavery – they were the ones who attacked, and it was about as anti-humanitarian as it was possible for a war to be until that guy in Germany … who?
I know this. I didn’t write anything that said the war was about “state’s rights.”
The above bears repeating. The South is the side that attacked. The North was simply responding. And despite what “everyone knew” about slavery ending if the North won – and early on in the war, it was by no means a given that slavery would end – the North did not have the end of slavery as an objective when it first sent troops into the South. Ending slavery did not become government policy until the Emancipation Proclamation in 1863, almost two full years after the start of the war, and even that covered only the states in rebellion. It did not cover the four Border States under Union control(Missouri, Kentucky, Maryland and Delaware), where separate decrees were required later on to end slavery there.
Doesn’t the 1979 failed rescue attempt of US embassy employees in Iran count?
I would not think so. 
Ngooork!