Things we believed during the Cold War that ended up being wrong

The Guardian has the details. In 1950, David was called to testify before a grand jury against the Rosenbergs. This was a different hearing than the 1951 trial that would result in Ethel's death sentence, but you wouldn't expect David's testimony to be substantially different. Yet different it was. In 1950, David repeatedly told those present that he had no knowledge of Ethel's involvement with Julius's spying. In 1951, he claimed to have seen her typing out notes to send to Moscow, an explosive claim that helped book Ethel a front row seat for her own execution. What changed between 1950 and 1951? David may have realized he preferred sex to sisterly affection. The Guardian article theorizes David's wife, Ruth, really played the typist role that Ethel was convicted for. It also implies David may have thrown Ethel under the bus to save his wife. Worst brother ever, or best husband? Discuss.