Bottom line: Columbia could not have reached the ISS. That adds to the 'it doesn't smell right' when they kept insisting that it made no sense to look for tile damage caused at launch, because they have no capability to repair tiles in orbit...
Something tells me, that might have originally been said about Apollo 13, but when faced with the situation they figured out a way, to bring them back.
Skynews website has a British scientist quoted as saying that NASA knew this ending was going to happen after finding out about the damaged tile, but couldn't do a damn thing about it. In other words, it was a sealed fate once the tile was hit upon liftoff. Guy seemed pretty sure of himself.