He may not support war but that doesn't mean there won't be one. If China attacks Taiwan, or if North Korea attack the South there will be a war in which the US will take part, despite of whoever they choose to be the president. There will also be a war if Russia uses nukes or of Russia attacks a NATO country...
IMO Biden has no chance for reelection. He's too old and is proving to be weak. A weak president makes the country look weak.