of the month. the deadline for u.s. troops to withdrawal. but he warned there are still risks. >> this evacuation mission is dangerous. it involves risks to our armed forces and it's being conducted under difficult circumstances. i cannot promise what the final outcome will be or it will be -- that it will be without risk of loss. but as commander in chief, i can assure you that i will mobilize every resource necessary. >> reporter: biden, also, facing fresh questions about why he didn't act sooner to bring americans and afghans home after diplomats sent a classified cable in mid-july warning a u.s. withdrawal would lead to the collapse of the u.s.-backed government. >> all kinds of cables. all kinds of advice. i made the decision. the buck stops with me. i took the consensus opinion. the consensus opinion was that, in fact, it would not occur if