Does this mean that the U.S. recognized the various Indian tribes as countries?
Lincoln's successors gave the Indians the same thing Lincoln gave the South: bullets and buckets of blood.
Only Lincoln wouldn't even give the Southerners a treaty to go along with the canister and gunpowder.
At least he didn't try to spread smallpox in the South.
No, it recognizes them as 'domestic dependent nations', a quasi-sovereign status which means that they exercise control over their reservations but have no international legal status. Constitutionally only the federal government can deal with Indian tribes and treaties signed with them are placed on the same level as international treaties.