Article I, Section 9: "The privilege of the Writ of Habeas Corpus shall not be suspended, unless when in Cases of Rebellion or Invasion the public Safety may require it."
Note the Article: One. Article I deals with Congress, not the executive. The scandal is not that habeas corpus was suspended--clearly, Congress has the right to do so--the scandal is that Lincoln, without the approval of Congress, suspended habeas corpus and then ignored a ruling from the Chief Justice that his actions were unconstitutional.