I know that's a big thing right now; but does his 'work' for the FBI invalidate his remarkable photographs?
I think a photographers work must stand alone. I frankly don't give a damn about an artist's political leanings.
Would his work have any more meaning were he to have been a member of the Communist Party?
I would agree! A photographers work should and mostly speak for itself. I vaguely recall that Margaret Burke-White was looked into becasue of her involvement with the early days of the Communist Russia. Then there is the whole history of Edward Weston's old flame in Mexico, Tina M.
She was very mixed up with that conutry's political past.
To me, there's a world of difference between an artist having a political leaning, and betrayal of the confidence conferred by your profession. Photographers often depend on special access and acting as a paid spy is a betrayal of the most basic ethics of journalism. It erodes trust in photographers and journalists and that weakens democracy.
I think there was a lot of pressure from the FBI on people like Withers, and I'm sure he wasn't making much money on his pictures, they're certainly worth a lot more today. And, as Robert says, perhaps there is a bit of "keep you friends close, keep your enemies closer" in his dealing with the FBI. It strikes me as a bit out of character, so perhaps the benefit of doubt is in order here.