Non sequitur. If Carlson's claim is false, there could be a myriad of reasons why there isn't a lawsuit, with the umbrella reasoning being that for an underlying cause, Raskin feels he benefits from leaving the claim in the open. My personal explanation would be that the two of them are working together to create smoke and mirrors presenting the illusion of public discourse, but I could also understand an explanation that Raskin feels his blue-leaning career benefits from being a public enemy of the red. I don't believe there exists division in the uniparty, but if you want to follow that belief, it's still possible to understand why a false claim would be allowed to stand. In the hypothetical world where elections aren't completely rigged at every level, a blue candidate would benefit from allowing an obvious lie to stand without devolving into the pageantry of a lawsuit. It's called "high-roading".