I can guarantee you that the Bundeswehr would have been able to secure the appropriate border locations and suitably intern, then screen the first waves of migrants / refugees. It would have then been a significant deterrent to the following migrant hordes and it would not have been sustained.

Unfortunately the German government (and others) did not identify the gravity of their situation and show anything like timely decision-making with the requisite determination to deal with it. Any responsible government's first duty is to defend and protect and its citizens. Germans will question whether Merkel has failed in that basic task.