I think Obama needs to make a definite decision: To stay in Afghanistan until the desired results are achieved or Get out of Afghanistan. If Obama wants to stay in Afghanistan than, atleast for now, some 50k more US troops needs to be send immediately. And remember don’t expect to get the situation in Afghanistan be normalized in 5 years, this roughly means 7-8 more years from now you’ll witness US troops geting out of Afghanistam. Also if attacks like this continues then Obama will have to send even more troops in the coming years.