If he was involved with the Cambridge ring, then he wasn't all that "straight".
Straight’s handlers put him in contact with Baldwin.
That implies that Baldwin independently had Chekist hoods on his Rolodex and suggests that he had already gone to work for them.
Last of the Cold War Spies; The Life of Michael Straight
The Only American in Britain's Cambridge Spy Ring
Roland Perry
Da Capo Press 2005
Pages 88-89: Straight bought a red convertible in New York, and he and Simonds drove north to the Adirondack Mountains, to meet up with Roger Baldwin, the 53-year-old lawyer running the American Civil Liberties Union (ACLU). Straight's communist contacts had linked him up with Baldwin. Straight had offered to chauffeur him on a tour of the centers of unrest in the industrial midwest and to "help while he makes speeches to local civil liberties groups, " if he would let him and Simonds come with him. His union would turn up wherever there was trouble to add comrade support to the communist controlled unions of the CIO . . . The communist aim was first to unionized, then to disrupt in order to weaken the United State's industrial might. The long-term aim (a decade or more) was to have the union and political base so powerful that a communist revolution would be possible.This was Straight's first observance of communist agitation and disruption in the United States. Later, he would make an art form of latching on to a respectable "liberal" front such as the ACLU and presenting himself as a concerned libertarian . . .
The final leg of the tour was through New York. Straight celebrated his 21st birthday on Sept, 1 1937, en route as Baldwin delivered militant speeches at meetings in several states. He attacked corporations for violating their employee's civil rights; Straight was impressed and stimulated.
Straight was the owner of the New Republic. He lived of his mommy's trust fund. Perry relates how, during the worse of the depression, Straight told his handler he had $10,000 he didn't know what to do with. The Soviets told him to dump it into a House campaign in Texas (to a Democrat of course...one not an anti-communist as many in that state were).