The case before the court in Ex Parte Bollman & Swartwout involved not who could suspend habeas corpus, but whether the court could issue a writ of habeas corpus or not. Since habeas corpus had not been suspended at the time, the court could not rule on the legality of the suspension so the Chief Justices comments on this matter constitute an obiter dictum; that which is said by the way or in passing. In law, an obiter dictum is an opinion expressed by a judge on a point of law not necessarily connected with the issue before the court. Obiter dicta have no binding authority. The comments Chief Justice Marshall made in Bollman & Swartwout concerning the suspension of habeas corpus were not part of the matter before the court. His comments on this unrelated matter have no standing in law other than an indication of how Marshall felt on that particular subject. When President Lincoln suspended habeas corpus on his own authority he violated no Suprem Court decision.
Why not? Marshall wrote:
'If the act of congress gives this court the power to award a writ of habeas corpus in the present case, it remains to inquire whether that act be compatible with the constitution.'Article I, § 9 - of the Constitution, a legislative power which 'herein granted shall be vested in a Congress of the United States, which shall consist of a Senate and House of Representatives', explicitly states that 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.''... If at any time the public safety should require the suspension of the powers vested by this act in the courts of the United States, it is for the legislature to say so.'
The Act in question must conform to the Constitution. The Contitution states that SUSPENDING the writ of habeas corpus is a legislative power. It's not a case where the legislature must craft legislation to put the grant into effect, it's a case where the legislature must enact legislation to suspend it. If it has NOT been suspended, the courts could obviously issue a writ. Which is exactly what Marshall had to decide. He wrote, 'the power to bring a person up that he may be tried in the proper jurisdiction is understood to be the very question now before the court.'
Only by answering the question of whether or not the legislature had suspended the writ could that question be decided. So instead of obiter dictum, Marshall's statement that the suspension of the writ is a legislative power is the foundation for the decision, not extranneous to it. Only IF the writ had been suspended by the legislature could the court be denied the 'power to bring a person up' on a writ of habeas corpus.