What is Cruel and Unusual?

In a continuing travesty of justice, the appeal of Richard Paey’s 25 year sentence for possessing his own pain medication was rejected by the Florida District Court of Appeals. For full details, see Radley Balko and Maia Szalavitz.
The dissent by Judge James Seals was the only positive moment:

suggest that it is cruel for a man with an undisputed medical need for a substantial amount of daily medication management to go to prison for twenty-five years for using self-help means to obtain and amply supply himself with the medicine he needed…
I suggest that it is unusual, illogical, and unjust that Mr. Paey could conceivably go to prison for a longer stretch for peacefully but unlawfully purchasing 100 oxycodone pills from a pharmacist than had he robbed the pharmacist at knife point, stolen fifty oxycodone pills which he intended to sell to children waiting outside, and then stabbed the pharmacist…
It is illogical, absurd, cruel, and unusual for the government to put Mr. Paey in prison for twenty-five years for foolishly and desperately pursuing his self-help solution to his medical management problems, and then go to prison only to find that the prison medical staff is prescribing the same or similar medication he had sought on the outside but could not legitimately obtain. That fact alone clearly proves what his intent for purchasing the drugs was. What a tragic irony.

The majority essentially said that they had no reason to question whether the sentence was cruel and unusual and that it was up to the legislature. Talk about defaulting on your charge to defend and interpret the constitution!
The thing is, I kind of understand it.
And it’s probably also the reason that the U.S. Supreme Court let Weldon Angelos’ 55-year prison term for marijuana stand by refusing to hear the case on Monday.
The courts just don’t know how to deal with the phrase “cruel and unusual.” How do you define it. If they say that Weldon’s 55 year sentence is cruel and unusual, then the obvious next question is “Well, what about 54? 53? 52? 51? 50?…” The courts are terrified at the notion of being asked to draw specific lines for every crime, so they simply buck it back to the legislature and shake their heads with sympathy for the poor person rotting in jail for the rest of their life. The Justices spend 8th Amendment efforts on debating what form of death penalty is the least painful and run away from the real issues.
Sure, it’s difficult. But it seems to me that it is the responsibility of the courts to find a way to address this. Otherwise they are completely abandoning the 8th Amendment to the whimsy of legislators, and sending the message that their is no jail term that is too long.