berlin lead candidates germany small party lock horn migration security foreign policy television debate monday come less three weeks federal election third-placed party could turn kingmaker clash follow debate centre-right chancellor angela merkel social democrat spd challenger martin schulz sunday hardly differences emerge stir speculation re-run current grand coalition conservative cdu/csu bloc spd likely outcome sept. 24 vote merkel schulz stress want avoid scenario poll suggest next government would stable majority another grand coalition tricky three-way coalition conservatives green business-friendly free democrats fdp debate small party cem ozdemir green attack die linke leave candidate sahra wagenknecht afd politician alice weidel euroceptic rhetoric anti-european populism simply wrong matter come far-left far-right ozdemir say add germany benefit immensely european union easy always blame brussels national problems member state weidel rightist anti-immigrant afd blame european central bank ultra-loose monetary policy soar rent property price german cities accuse ecb violate european treaties bond-buying program fdp candidate christian lindner try corner ozdemir accuse apply double standards foreign policy inconsistent approach toward russia lindner raise eyebrows last month suggest germany might accept russia 2014 annexation crimea region ukraine permanent provisional arrangement merkel condemn russia annexation crimea support anti-government separatists eastern ukraine lead europe maintain economic sanction moscow linder say germany mix refugee asylum policies need modern well-directed immigration law attract highly educate workers abroad avert shortage skilled labor germany turn threat islamist attack lindner say need tough security laws add last year christmas market attack berlin fail asylum seeker could probably avert authorities implement exist laws strictly afd weidel call tough border control improve security suggest upper limit 10,000 refugees per year bavarian csu conservatives want official cap 200,000 refugees per year proposal oppose merkel co-governing social democrats spd trail merkel conservative cdu/csu bloc double digits poll late survey emnid show sunday spd gain one percentage point 24 percent merkel conservatives remain unchanged 38 percent leftist die linke come percent make third-strongest political force green fdp afd stand percent mean six party expect enter bundestag low house parliament current four fracture political landscape could make hard form another viable alliance current grand coalition small german party fight third place possibly power tv debate