Depends. Whose policy would have taken hold instead?
Perhaps the holocaust would have been prevented, but war was inevitable. The Germans were (wrongly) blamed for EVERYTHING in WW1 (it's definitely a case of "everyone did it", though especially the Habsburg Monarchy, who was allies with Germany, not actually a part of Germany!) and I seriously doubt they would have let that slide with or without Hitler.
Even if they hadn't gone to war with half of Europe then, I suspect war was inevitably coming to Germany in the form of Red Russia, under the leadership of Stalin (Russian expansion would not be checked for long. Hell, WW1 was started in part due to pressures from England and France on the Habsburg Monarchy, asking the Monarchy to annex destabilized territories just so Russia wouldn't gain direct access to the Mediterranean! There were genuine reasons to fear Russia even before WW2 broke out).