[jmacusa]

So an article spelled out in the Constitution isn’t meant to do what it says? Why is it there then and why did FDR do much the same in WW2?

[BroJoeK]

jmacusa: "So an article spelled out in the Constitution isn’t meant to do what it says?
Why is it there then and why did FDR do much the same in WW2?"

rusty's correct point is that (per Article 1, Section 9) only Congress has constitutional authority to suspend habeas corpus, not the President on his own authority.

At the time of Lincoln's first suspension of habeas corpus, April 27, 1861, the issue was riots and rebellion in Maryland -- exactly those envisioned by the Founders in the Constitution.
However, Congress was not in session at the time, so Lincoln acted on his own.
When Congress returned, it took up the question of authorizing Lincoln's actions, and eventually approved:

"When Congress met again in December 1862, the House of Representatives passed a bill indemnifying the president for his suspension of habeas corpus.[15]
The Senate amended the bill,[16] and the compromise reported out of the conference committee altered it to remove the indemnity and to suspend habeas corpus on Congress's own authority.[17]

That bill, the Habeas Corpus Suspension Act, was signed into law March 3, 1863.[18]
Lincoln exercised his powers under it in September, suspending habeas corpus throughout the Union in any case involving prisoners of war, spies, traitors, or military personnel,[19]

The suspension of habeas corpus remained in effect until Andrew Johnson revoked it on December 1, 1865.[20]"

Jefferson Davis also suspended habeas corpus in the Confederacy:

"In the Confederacy, Jefferson Davis also suspended habeas corpus and imposed martial law.[23]
This was in part to maintain order and spur industrial growth in the South to compensate for the economic loss inflicted by its secession."

Without doubt, the constitutional power to suspend habeas corpus belongs to Congress, not the President.
However, on occasion, Congress has authorized the President to suspend habeas corpus on his own authority, notably in the Civil Rights act of 1871.

Today the right of habeas corpus is much in the news, regarding terrorists, but that's a whole other subject.