[rustbucket]

Perhaps because you're reading the law, and the Constitution wrong? The Constitution says that the Supreme Court will have original jurisdiction over matters involving foreign representatives or where states are involved. The Merryman matter involved neither of those, it was an entirely federal matter - U.S. Army, the President, and an individual. Maryland wasn't involved. So the Supreme Court only had appellate jurisdiction. So Taney could not issue a decision for the court, the matter had no business being before the court to begin with.

From Ex Parte Milligan:

The decision that the individual shall be imprisoned must always precede the application for a writ of habeas corpus, and this writ must always be for the purpose of revising that decision, and therefore appellate in its nature.

[rustbucket]

Whoops. I had so many sites open, I cited the wrong one for that statement. It was from Ex parte Bollman & Swartwout (1807). [Link]

[Non-Sequitur]

The decision that the individual shall be imprisoned must always precede the application for a writ of habeas corpus, and this writ must always be for the purpose of revising that decision, and therefore appellate in its nature.

And yet again, we are not talking about the issuing of a writ of habeas corpus and whether a Supreme Court justice can issue one. Taney could. We're talking about whether or not Ex Parte Merryman is a Supreme Court decision, and if a single Justice can issue a decision for the entire court. You insist that it is, and I keep pointing out how it can't be.