Justin Bieber -- Neutral in Lil Wayne/Scooter War

Justin Bieber is Switzerland when it comes to the beef between Lil Wayne and Biebs' manager, Scooter Braun ... giving them both shout-outs ... but giving Scooter top billing.

Bieber was leaving the Rainbow Bar and Grill on the Sunset Strip Tuesday night, and could not have been nicer to fans who wanted a pic.

Our photog asked Bieber about Lil Wayne's veiled death threat against Scooter. He clearly wanted to answer because he rolled the window back down to make one thing clear ... he would not clearly take sides.