The Case of Julius and Ethel Rosenberg
en.wikipedia.org
en.wikipedia.org
The Rosenbergs were passers-on. They facilitated information flow. They neither had access to the sources, nor really knew what they were doing. Intermediaries. Harry Gold and Greenglass were as complicit. Yet, it was the Rosenbergs who went to the chair.
At no time in WW2, or subsequenty, was the US "at war" with the USSR, and to kill the Rosenbergs when other choices existed was to me, not a signal of strength, any more than current political crises foment death sentences for individuals caught up in inter-state disputes. I wonder if they had been the individuals on hand when Gary Powers was captured (1960s), if the swap could have been done? Colonel Abel was a high value asset but also a soviet citizen. Rhodes makes a strong case that the russians will walk over hot coals to get their own back, but were prepared to throw foreign nationals who spied in their interests under the bus.
I expect few here agree with me, but none the less, I think Claus Fuchs was a brave, and moral man. I know people have strong views that accepting British citizenship placed him in a duty to his state, but I think his background led him inexorably to needing to do this, in his own moral compass. Fuchs went on to lead peaceful atomic power work in East Germany, and his contribution to the bomb is immense, and should not be minimised: he actively helped make the bomb work. He did the maths on implosions.
Likewise Helen and Peter Kroger. To deliberately construct a life like that, a dual persona, takes a lot of commitment and strength. I doubt I could carry it off.
I don't personally like the word traitor or treason. I think its a very loose term, but that said, it would be hard not to apply it here.