[Sloth]

All those things are true. I don’t defend the Confederacy. But it’s colossally hypocritical for the United States to forcibly deny secession to its constituent entities when the U.S. was itself formed by secession from the British empire.

[rockrr]

The United States wasn’t formed by secession from the British empire - It was formed after rebelling against the crown.

[BroJoeK]

Sloth: "it’s colossally hypocritical for the United States to forcibly deny secession to its constituent entities when the U.S. was itself formed by secession from the British empire."

Our Founders and everyone here defending Lincoln and Union acknowledge a "right to secede", lawfully and peacefully.
This could be by "mutual consent", meaning Congress approves, or through some "oppression" and "injury", suggesting a Supreme Court ruling.

But what none agree to is unilateral declarations of secession, in Madison's term, "at pleasure" -- meaning without any constitutionally justifying reasons.

The Founders' logic is simple: they considered their Constitution a legally binding contract, or "compact", similar to, let's say, a marriage which is only to be broken for the most serious of reasons, and even then preferably by mutual consent.

But in 1860 and 1861 secessionists did none of that.
Instead they unilaterally declared secession "at pleasure", and immediately began committing many acts of violent rebellion, insurrection and war against the United States, before formally declaring war on May 6, 1861.