Bedtime woes

I wish I knew how to fix our bedtime woes. Rose #1 and Rose #3 generally fall asleep pretty quickly, but Rose #2 haaaaaaaaaaaangs on, fussing, pouting, refusing to lay down, etc., etc., etc. Right now I am in the kitchen listening to H deal with her - it's his night to manage bedtime. We switch off every other night. It is not going well. She is 4 years old! Wouldn't you think most of our bedtime struggles would be behind us?