His vilification at the hands of the media (ironic, no?) coupled with an ambition which was the stuff of greek tragedy, brought his career to an ignominious end. He became increasingly erratic and depressed, and ended up pickling himself. A sad ending, to be sure, but if he had been Ted Kennedy, the media would have circled the wagons and excused his excesses until he finally decided to retire of his own volition.
I think what Ann is saying is that this guy - Evans - has uncovered facts concerning McCarthy that are different than what is printed about him. I remember in Treason, she wrote that when she was researching McCarthy, she found out that newspapers would use as sources what other newspapers wrote. That she would have to dig and dig to try to uncover the original source, which in fact turned out to something somone made up. I think what Ann is saying about this new book is that what we post and state about McCarthy are in fact, the lies printed about him in over fifty years of the liberals smearing him.