The unusual split comes at a time when mainstream politicians have accused the anti-immigration AfD of acting as stooges for the Kremlin and even spying for Russia. The row has also erupted in a year in which the AfD is flying high, often polling above the record 20 percent it won in the February elections which made it Germany's second strongest party.
The more left-wing members of the Social Democrats have accused their party leadership of doing too little to secure peace in Europe, calling for peacekeeping through defense capabilities, arms control, and rapprochement.