[Vlad The Inhaler]

For starters, Federal ownership of many seized properties throughout the South, including forts, ships, arsenals & mints.

Did they belong to the Federal government or to the people?

And were they worth 600,000 lives?

[BroJoeK]

Glad The Inhaler: "Did they belong to the Federal government or to the people?
And were they worth 600,000 lives?"

Federal territories, forts, ships, arsenals & mints, lighthouses, etc. belonged under Constitutional authority of Congress.
The situation was analogous to our base at Guantanamo, Cuba after the Commie Cuban takeover.
Commies reject US treaty rights there and don't accept our lease payments, but if they launch a military assault to remove our troops, that is an act of war for which they will be responsible.
In the mean time our guys in Gitmo are supplied or reinforced at will regardless of Commie Cuban squawking.

Just like Fort Sumter.

As for 600,000 lives, remember, Confederates could have stopped the war on any day before April 1865 on much better terms than the Unconditional Surrender they fought so hard to achieve.