Yes it is per the unanimous assertions of every founding father who ever wrote on this issue and per its placement in Article I.
2. Not a single founding father thought that the Union was frangible either.
False. Jefferson indisputably did as his 1803 letter on the Louisiana Purchase indicates. He is by far the most prominent to hold this belief but by no means the only. It is also true that when the founders drafted the habeas corpus clause they all recognized the possibility of events that some would call a rebellion. Some, such as Luther Martin, openly anticipated a day when some states would get into a war with the federal government. Despite this knowledge they did not alter so much as one word of their habeas corpus policy, which remained with the legislature and legislature alone.
The absurdity of your position will be manfest to anyone who can think.
The only absurdity here, Walt, is your belief that the Constitution gives the habeas corpus power to anybody other that Congress despite the fact that it explicitly places it within the congressional powers. To believe your position one must completely disregard the unanimous writings of the founding fathers themselves, the rulings of two well respected chief justices (Marshall and Taney), the legal scholarship of four well respected early American jurists, two of them also members of the supreme court itself (Tucker, Rawle, Story, and Curtis), and the common straight forward words of the Constitution itself. Such nonsense is the same process by which the meaning of "is" comes into dispute and by which a horse chestnut becomes a chestnut horse. You know this to be the case, Walt, because how could you not after all the tortured legal leaps, bounds, and bizarre word gymnastics you must by necessity play in order to even express your position let alone defend it!
Under your interpretation, the Writ could only be suspended when Cnngress was in session.
Exactly, and it is that way for a reason: to make the president call Congress into session during cases that merit the suspension of habeas corpus.
Quite right. Note that Article I Section 9 contains limitations on the legislative powers of Congress (Congress's right to suspend habeas corpus being limited to where in cases of rebellion or invasion the public safety requires such suspension.) And it immediately follows Article I Sectio0n 8, on the positive extent of the legislative powers of Congress.