In the comments on my epic post about J.B.S. Haldane, somebody else named Jeremy (not me, I swear) links to a fantastic video of Haldane's scientific colleague (and fellow former British Communist) John Maynard Smith, discussing Haldane's opposition to Lysenkoism. Specifically, what Haldane said in private within Communist circles, versus what he didn't say in the broader public.
I think it's quite clear that Haldane should have objected to the politicization of Lysenko's bunk science much earlier and more forcefully than he did. Whether it would've made a difference behind the Iron Curtain is less certain.