The Campaign of the Century. This was the amazingly influential 1934 race in California when socialist author Upton Sinclair nearly won the governor's post--and inspired the GOP, the special interests and Hollywood to invent the modern political campaign, with dirty tricks galore.
I'm not sure why they are re-airing now, beyond the relevance for this year's race, but perhaps they read last month's major New Yorker piece that was inspired by the same campaign. Listen to the segment here.
And here's my video on the Thalberg newsreels, the first attacks ads on the screen.