Isn't that how Le Pen's party was able to cause havoc in France? By gaining a large enough minority to be a contender for coalition-building and then exploiting it to exert control?

I'm not too up to speed, but I feel like I remember them causing significant fuckage with exactly that mechanism.

Edit: And, presumably, the left will inevitably feel it needs to stomp its feet and scream that the center isn't left enough, so no way we can cooperate with those guys, leaving the center to appease the Nazis if they want to get anything done.