“I seriously doubt a democrat would cross over and vote for a Republican “
I could see a couple doing that, e.g., Manchin. They don’t want a GOP, but can live with McCarthy. After all, he’s voted with them often, selling out our side. They might think the devil they know is better than the devil they don’t know. He’d be better for them than someone more conservative.
One thing the Democrats have is discipline and punishment for anyone crossing the line, the activists on the left would crucify the person and remove them from all committees and primary them