Lincoln addressed this, although discussing another subject.
"I did understand however that my oath to preserve the constitution to the best of my ability, imposed upon me the duty of preserving by every indispensible means, that government--that nation--of which that constitution was the organic law. Was it possible to lose the nation, and preserve the constitution? By general law life and limb must be protected; yet often a limb must be amputated to save a life; but a life is never wisely given to save a limb. I felt that measures, otherwise unconstitutional, might become lawful, by becoming indispensible to to the preservation of the of the Constitution, through the preservation of the nation. Right or wrong, I assumed this ground, and now avow it..."
The issue of whether the president may or may not suspend the writ has not been definitively answered to this day.
Walt