Professor,
The WaPo was a willing participant in the original story, in spite of the fact that many ... on the left, as well as the right ... warned from the get-go that this story was fishy. I think the WaPo started getting cold feet about Khan's claim and decided to actually do its job (i.e., actually some take steps to investigate the veracity of the claim, instead of simply swallowing hook, line, and sinker with leftist, religious fervor - just like Cactus Flower, clo, and zzfart did, by the way). The WaPo hasn't changed its bigoted, intolerant, anti-American stripes any ... its just wanting to do some CYA groundwork given the increasing likelihood that Khan's story turns out to be a farce.
B.
The essential American soul is hard, isolate, stoic, and a killer. It has never yet melted. ~ D.H. Lawrence