Correspondent Claire Shipman explained, "It's another feud in an often fractious family. In a series of tweets over the weekend, Michael Reagan, the former President's son and a conservative commentator, accused his stepbrother Ron of trying to sell out his father to sell books."
As the MRC's Brent Baker  pointed out, Ron Reagan Jr. previously hosted a show on the left-wing MSNBC and now appears on the network to provide liberal commentary. On Sunday's World News, reporter David Muir also identified the politics of Michael, but not Ron Reagan.
Shipman played clips from a 20/20 appearance last Friday in which Reagan Jr. promoted his book and asserted that he simply had an "inkling" that his father had Alzheimer's in the White House. (In the actual 20/20 segment, Elizabeth Vargas, unlike Muir and Shipman, referred to Ron Reagan Jr. As a "Democrat." That part, however, didn't air on GMA.)
Ron Reagan is not a medical doctor and Shipman didn't point out that there's evidence for this claim. Instead, she parroted, "Ron also writes 'I've seen no evidence that my father, or anyone else, was aware of his medical condition while he was in office. Had the diagnosis been made in, say, 1987, would he have stepped down? I believe he would have.'"
The liberal author will appear on Tuesday's GMA to promote his book. Will his ideology be mentioned by host George Stephanopoulos?
A transcript of the January 17 segment, which aired at 7:11am EST, follows: