Once again, it's the coverup, stupid. Obama could have done it the right way and although, Walpin might not have liked it, he would have little recourse.
But in their haste to fire him, the skirted the laws - laws that Obama was even involved in writing and to justify that mistake, they impugned his character by claiming he was incoherent and incompetent. Up to that point, maybe he would have gone away, but as a proud man, he is determined to get his reputation back.
Wonder who the Obama version of Craig Livingstone will be.