[BroJoeK]

jeffersondem quoting London Spectator: "The principle is not that a human being cannot justly own another, but that he cannot own him unless he is loyal to the United States.”

Indeed, as jeffersondem so gleefully points out, the Constitution "enshrined" slavery for loyal States.
But for States at war against the United States, laws of war allowed US officials to declare "contraband of war" and so they did, thus simultaneously moving to defeat the rebellion and accomplish their long term moral goals.

So it was a win-win for the Union, for the Confederacy it was a stake in the heart.

[jeffersondem]

“. . . and so they (Lincoln officials) did, thus simultaneously moving to defeat the rebellion and accomplish their long term moral goals.”

In his “House Divided” speech Lincoln expressed the expectation that one way or the other constitutional slavery would end.

Everyone, North and South, knew Lincoln would not likely have the votes to end constitutional slavery peacefully in his lifetime using the amendment process.

However, if he could parlay 39 percent of the popular vote into a presidency; if he could gain control of the military he could levy war against the states and violently overthrow constitutional slavery. And the Constitution.

First he would need a pretext for war. This he found using the navy in the Gulf of Tonkin Incident.

I meant to say, the Fort Sumter Incident.