Harding was truly terrible. He (along with Hoover & Grant, though Grant has been rehabbed a bit of late) usually completes the bottom of the barrel presidents along with A. Johnson, Pierce & Buchanan They usually throw in WH Harrison too, but the guy was up there for like a couple of months before he died...I would just give him an "Inc." though Tippecanoe probably would have sucked, like Tyler too.
I don't want to be rude, but listing the Iran-Contra Arms-for-Hostages as something that Carter should have done before leaving office is sort of like talking about the BJ that George H. Bush missed by not hireing Monica, or faulting LBJ for missing his oportunity to break into the Watergate before Nixon beat him to it. Whatever you think of the man and even if you somehow still believe that none of the top White House officials knew, the entire mess is on his doorstep, and he has to take credit for one of the lowest point of his entire history of the presidency, for a scandal as disgraceful as any of the other political scandals in American history. Carter should be proud that he didn't offer to trade weapons to a bunch of Radical Islamic terrorists in exchange for some political capital. So far, one of the admirable traits of GW is that, for better or worse, he is sticking to his guns in Iraq, even when it's costing him dearly.