For a decade and half, the spoiler factor has been a third rail of progressive politics.
Some of those who have raised the issue are genuinely concerned with the prospect of a third party candidate enabling a far right victory.
But others are Democratic Party operatives who, in Matt Taibbi’s phrase, “would triangulate their own mothers” to maintain their lock on power. Spoiling for them is a bad faith exercise in maintaining electoral politics as a bipartisan gated community from which left, populist candidates are excluded.